2018 – The Year of the Segment

Looking in the rear view mirror, what a year! Some days it’s been hard to catch your breath things have been moving so fast.

What were the major happenings, how did they affect genetic genealogy and what’s coming in 2019?

The SNiPPY Award

First of all, I’m giving an award this year. The SNiPPY.

Yea, I know it’s kinda hokey, but it’s my way of saying a huge thank you to someone in this field who has made a remarkable contribution and that deserves special recognition.

Who will it be this year?

Drum roll…….

The 2018 SNiPPY goes to…

DNAPainter – The 2018 SNiPPY award goes to DNAPainter, without question. Applause, everyone, applause! And congratulations to Jonny Perl, pictured below at Rootstech!

Jonny Perl created this wonderful, visual tool that allows you to paint your matches with people on your chromosomes, assigning the match to specific ancestors.

I’ve written about how to use the tool  with different vendors results and have discovered many different ways to utilize the painted segments. The DNA Painter User Group is here on Facebook. I use DNAPainter EVERY SINGLE DAY to solve a wide variety of challenges.

What else has happened this year? A lot!

Ancient DNA – Academic research seldom reports on Y and mitochondrial DNA today and is firmly focused on sequencing ancient DNA. Ancient genome sequencing has only recently been developed to a state where at least some remains can be successfully sequenced, but it’s going great guns now. Take a look at Jennifer Raff’s article in Forbes that discusses ancient DNA findings in the Americas, Europe, Southeast Asia and perhaps most surprising, a first generation descendant of a Neanderthal and a Denisovan.

From Early human dispersals within the Americas by Moreno-Mayer et al, Science 07 Dec 2018

Inroads were made into deeper understanding of human migration in the Americas as well in the paper Early human dispersals within the Americas by Moreno-Mayer et al.

I look for 2019 and on into the future to hold many more revelations thanks to ancient DNA sequencing as well as using those sequences to assist in understanding the migration patterns of ancient people that eventually became us.

Barbara Rae-Venter and the Golden State Killer Case

Using techniques that adoptees use to identify their close relatives and eventually, their parents, Barbara Rae-Venter assisted law enforcement with identifying the man, Joseph DeAngelo, accused (not yet convicted) of being the Golden State Killer (GSK).

A very large congratulations to Barbara, a retired patent attorney who is also a genealogist. Nature recognized Ms. Rae-Venter as one of 2018’s 10 People Who Mattered in Science.

DNA in the News

DNA is also represented on the 2018 Nature list by Viviane Slon, a palaeogeneticist who discovered an ancient half Neanderthal, half Denisovan individual and sequenced their DNA and He JianKui, a Chinese scientist who claims to have created a gene-edited baby which has sparked widespread controversy. As of the end of the year, He Jiankui’s research activities have been suspended and he is reportedly sequestered in his apartment, under guard, although the details are far from clear.

In 2013, 23andMe patented the technology for designer babies and I removed my kit from their research program. I was concerned at the time that this technology knife could cut two ways, both for good, eliminating fatal disease-causing mutations and also for ethically questionable practices, such as eugenics. I was told at the time that my fears were unfounded, because that “couldn’t be done.” Well, 5 years later, here we are. I expect the debate about the ethics and eventual regulation of gene-editing will rage globally for years to come.

Elizabeth Warren’s DNA was also in the news when she took a DNA test in response to political challenges. I wrote about what those results meant scientifically, here. This topic became highly volatile and politicized, with everyone seeming to have a very strongly held opinion. Regardless of where you fall on that opinion spectrum (and no, please do not post political comments as they will not be approved), the topic is likely to surface again in 2019 due to the fact that Elizabeth Warren has just today announced her intention to run for President. The good news is that DNA testing will likely be discussed, sparking curiosity in some people, perhaps encouraging them to test. The bad news is that some of the discussion may be unpleasant at best, and incorrect click-bait at worst. We’ve already had a rather unpleasant sampling of this.

Law Enforcement and Genetic Genealogy

The Golden State Killer case sparked widespread controversy about using GedMatch and potentially other genetic genealogy data bases to assist in catching people who have committed violent crimes, such as rape and murder.

GedMatch, the database used for the GSK case has made it very clear in their terms and conditions that DNA matches may be used for both adoptees seeking their families and for other uses, such as law enforcement seeking matches to DNA sequenced during a criminal investigation. Since April 2018, more than 15 cold case investigations have been solved using the same technique and results at GedMatch. Initially some people removed their DNA from GedMatch, but it appears that the overwhelming sentiment, based on uploads, is that people either aren’t concerned or welcome the opportunity for their DNA matches to assist apprehending criminals.

Parabon Nanolabs in May established a genetic genealogy division headed by CeCe Moore who has worked in the adoptee community for the past several years. The division specializes in DNA testing forensic samples and then assisting law enforcement with the associated genetic genealogy.

Currently, GedMatch is the only vendor supporting the use of forensic sample matching. Neither 23anMe nor Ancestry allow uploaded data, and MyHeritage and Family Tree DNA’s terms of service currently preclude this type of use.

MyHeritage

Wow talk about coming onto the DNA world stage with a boom.

MyHeritage went from a somewhat wobbly DNA start about 2 years ago to rolling out a chromosome browser at the end of January and adding important features such as SmartMatching which matches your DNA and your family trees. Add triangulation to this mixture, along with record matching, and you’re got a #1 winning combination.

It was Gilad Japhet, the MyHeritage CEO who at Rootstech who christened 2018 “The Year of the Segment,” and I do believe he was right. Additionally, he announced that MyHeritage partnered with the adoption community by offering 15,000 free kits to adoptees.

In November, MyHeritage hosted MyHeritage LIVE, their first user conference in Oslo, Norway which focused on both their genealogical records offerings as well as DNA. This was a resounding success and I hope MyHeritage will continue to sponsor conferences and invest in DNA. You can test your DNA at MyHeritage or upload your results from other vendors (instructions here). You can follow my journey and the conference in Olso here, here, here, here and here.

GDPR

GDPR caused a lot of misery, and I’m glad the implementation is behind us, but the the ripples will be affecting everyone for years to come.

GDPR, the European Data Protection Regulation which went into effect on May 25,  2018 has been a mixed and confusing bag for genetic genealogy. I think the concept of users being in charge and understanding what is happened with their data, and in this case, their data plus their DNA, is absolutely sound. The requirements however, were created without any consideration to this industry – which is small by comparison to the Googles and Facebooks of the world. However, the Googles and Facebooks of the world along with many larger vendors seem to have skated, at least somewhat.

Other companies shut their doors or restricted their offerings in other ways, such as World Families Network and Oxford Ancestors. Vendors such as Ancestry and Family Tree DNA had to make unpopular changes in how their users interface with their software – in essence making genetic genealogy more difficult without any corresponding positive return. The potential fines, 20 million plus Euro for any company holding data for EU residents made it unwise to ignore the mandates.

In the genetic genealogy space, the shuttering of both YSearch and MitoSearch was heartbreaking, because that was the only location where you could actually compare Y STR and mitochondrial HVR1/2 results. Not everyone uploaded their results, and the sites had not been updated in a number of years, but the closure due to GDPR was still a community loss.

Today, mitoydna.org, a nonprofit comprised of genetic genealogists, is making strides in replacing that lost functionality, plus, hopefully more.

On to more positive events.

Family Tree DNA

In April, Family Tree DNA announced a new version of the Big Y test, the Big Y-500 in which at least 389 additional STR markers are included with the Big Y test, for free. If you’re lucky, you’ll receive between 389 and 439 new markers, depending on how many STR markers above 111 have quality reads. All customers are guaranteed a minimum of 500 STR markers in total. Matching was implemented in December.

These additional STR markers allow genealogists to assemble additional line marker mutations to more granularly identify specific male lineages. In other words, maybe I can finally figure out a line marker mutation that will differentiate my ancestor’s line from other sons of my founding ancestor😊

In June, Family Tree DNA announced that they had named more than 100,000 SNPs which means many haplogroup additions to the Y tree. Then, in September, Family Tree DNA published their Y haplotree, with locations, publicly for all to reference.

I was very pleased to see this development, because Family Tree DNA clearly has the largest Y database in the industry, by far, and now everyone can reap the benefits.

In October, Family Tree DNA published their mitochondrial tree publicly as well, with corresponding haplogroup locations. It’s nice that Family Tree DNA continues to be the science company.

You can test your Y DNA, mitochondrial or autosomal (Family Finder) at Family Tree DNA. They are the only vendor offering full Y and mitochondrial services complete with matching.

2018 Conferences

Of course, there are always the national conferences we’re familiar with, but more and more, online conferences are becoming available, as well as some sessions from the more traditional conferences.

I attended Rootstech in Salt Lake City in February (brrrr), which was lots of fun because I got to meet and visit with so many people including Mags Gaulden, above, who is a WikiTree volunteer and writes at Grandma’s Genes, but as a relatively expensive conference to attend, Rootstech was pretty miserable. Rootstech has reportedly made changes and I hope it’s much better for attendees in 2019. My attendance is very doubtful, although I vacillate back and forth.

On the other hand, the MyHeritage LIVE conference was amazing with both livestreamed and recorded sessions which are now available free here along with many others at Legacy Family Tree Webinars.

Family Tree University held a Virtual DNA Conference in June and those sessions, along with others, are available for subscribers to view.

The Virtual Genealogical Association was formed for those who find it difficult or impossible to participate in local associations. They too are focused on education via webinars.

Genetic Genealogy Ireland continues to provide their yearly conference sessions both livestreamed and recorded for free. These aren’t just for people with Irish genealogy. Everyone can benefit and I enjoy them immensely.

Bottom line, you can sit at home and educate yourself now. Technology is wonderful!

2019 Conferences

In 2019, I’ll be speaking at the National Genealogical Society Family History Conference, Journey of Discovery, in St. Charles, providing the Special Thursday Session titled “DNA: King Arthur’s Mighty Genetic Lightsaber” about how to use DNA to break through brick walls. I’ll also see attendees at Saturday lunch when I’ll be providing a fun session titled “Twists and Turns in the Genetic Road.” This is going to be a great conference with a wonderful lineup of speakers. Hope to see you there.

There may be more speaking engagements at conferences on my 2019 schedule, so stay tuned!

The Leeds Method

In September, Dana Leeds publicized The Leeds Method, another way of grouping your matches that clusters matches in a way that indicates your four grandparents.

I combine the Leeds method with DNAPainter. Great job Dana!

Genetic Affairs

In December, Genetic Affairs introduced an inexpensive subscription reporting and visual clustering methodology, but you can try it for free.

I love this grouping tool. I have already found connections I didn’t know existed previously. I suggest joining the Genetic Affairs User Group on Facebook.

DNAGedcom.com

I wrote an article in January about how to use the DNAGedcom.com client to download the trees of all of your matches and sort to find specific surnames or locations of their ancestors.

However, in December, DNAGedcom.com added another feature with their new DNAGedcom client just released that downloads your match information from all vendors, compiles it and then forms clusters. They have worked with Dana Leeds on this, so it’s a combination of the various methodologies discussed above. I have not worked with the new tool yet, as it has just been released, but Kitty Cooper has and writes about it here.  If you are interested in this approach, I would suggest joining the Facebook DNAGedcom User Group.

Rootsfinder

I have not had a chance to work with Rootsfinder beyond the very basics, but Rootsfinder provides genetic network displays for people that you match, as well as triangulated views. Genetic networks visualizations are great ways to discern patterns. The tool creates match or triangulation groups automatically for you.

Training videos are available at the website and you can join the Rootsfinder DNA Tools group at Facebook.

Chips and Imputation

Illumina, the chip maker that provides the DNA chips that most vendors use to test changed from the OmniExpress to the GSA chip during the past year. Older chips have been available, but won’t be forever.

The newer GSA chip is only partially compatible with the OmniExpress chip, providing limited overlap between the older and the new results. This has forced the vendors to use imputation to equalize the playing field between the chips, so to speak.

This has also caused a significant hardship for GedMatch who is now in the position of trying to match reasonably between many different chips that sometimes overlap minimally. GedMatch introduced Genesis as a sandbox beta version previously, but are now in the process of combining regular GedMatch and Genesis into one. Yes, there are problems and matching challenges. Patience is the key word as the various vendors and GedMatch adapt and improve their required migration to imputation.

DNA Central

In June Blaine Bettinger announced DNACentral, an online monthly or yearly subscription site as well as a monthly newsletter that covers news in the genetic genealogy industry.

Many educators in the industry have created seminars for DNACentral. I just finished recording “Getting the Most out of Y DNA” for Blaine.

Even though I work in this industry, I still subscribed – initially to show support for Blaine, thinking I might not get much out of the newsletter. I’m pleased to say that I was wrong. I enjoy the newsletter and will be watching sessions in the Course Library and the Monthly Webinars soon.

If you or someone you know is looking for “how to” videos for each vendor, DNACentral offers “Now What” courses for Ancestry, MyHeritage, 23andMe, Family Tree DNA and Living DNA in addition to topic specific sessions like the X chromosome, for example.

Social Media

2018 has seen a huge jump in social media usage which is both bad and good. The good news is that many new people are engaged. The bad news is that people often given faulty advice and for new people, it’s very difficult (nigh on impossible) to tell who is credible and who isn’t. I created a Help page for just this reason.

You can help with this issue by recommending subscribing to these three blogs, not just reading an article, to newbies or people seeking answers.

Always feel free to post links to my articles on any social media platform. Share, retweet, whatever it takes to get the words out!

The general genetic genealogy social media group I would recommend if I were to select only one would be Genetic Genealogy Tips and Techniques. It’s quite large but well-managed and remains positive.

I’m a member of many additional groups, several of which are vendor or interest specific.

Genetic Snakeoil

Now the bad news. Everyone had noticed the popularity of DNA testing – including shady characters.

Be careful, very VERY careful who you purchase products from and where you upload your DNA data.

If something is free, and you’re not within a well-known community, then YOU ARE THE PRODUCT. If it sounds too good to be true, it probably is. If it sounds shady or questionable, it’s probably that and more, or less.

If reputable people and vendors tell you that no, they really can’t determine your Native American tribe, for example, no other vendor can either. Just yesterday, a cousin sent me a link to a “tribe” in Canada that will, “for $50, we find one of your aboriginal ancestors and the nation stamps it.” On their list of aboriginal people we find one of my ancestors who, based on mitochondrial DNA tests, is clearly NOT aboriginal. Snake oil comes in lots of flavors with snake oil salesmen looking to prey on other people’s desires.

When considering DNA testing or transfers, make sure you fully understand the terms and conditions, where your DNA is going, who is doing what with it, and your recourse. Yes, read every single word of those terms and conditions. For more about legalities, check out Judy Russell’s blog.

Recommended Vendors

All those DNA tests look yummy-good, but in terms of vendors, I heartily recommend staying within the known credible vendors, as follows (in alphabetical order).

For genetic genealogy for ethnicity AND matching:

  • 23andMe
  • Ancestry
  • Family Tree DNA
  • GedMatch (not a vendor because they don’t test DNA, but a reputable third party)
  • MyHeritage

You can read about Which DNA Test is Best here although I need to update this article to reflect the 2018 additions by MyHeritage.

Understand that both 23andMe and Ancestry will sell your DNA if you consent and if you consent, you will not know who is using your DNA, where, or for what purposes. Neither Family Tree DNA, GedMatch, MyHeritage, Genographic Project, Insitome, Promethease nor LivingDNA sell your DNA.

The next group of vendors offers ethnicity without matching:

  • Genographic Project by National Geographic Society
  • Insitome
  • LivingDNA (currently working on matching, but not released yet)

Health (as a consumer, meaning you receive the results)

Medical (as a contributor, meaning you are contributing your DNA for research)

  • 23andMe
  • Ancestry
  • DNA.Land (not a testing vendor, doesn’t test DNA)

There are a few other niche vendors known for specific things within the genetic genealogy community, many of whom are mentioned in this article, but other than known vendors, buyer beware. If you don’t see them listed or discussed on my blog, there’s probably a reason.

What’s Coming in 2019

Just like we couldn’t have foreseen much of what happened in 2018, we don’t have access to a 2019 crystal ball, but it looks like 2019 is taking off like a rocket. We do know about a few things to look for:

  • MyHeritage is waiting to see if envelope and stamp DNA extractions are successful so that they can be added to their database.
  • www.totheletterDNA.com is extracting (attempting to) and processing DNA from stamps and envelopes for several people in the community. Hopefully they will be successful.
  • LivingDNA has been working on matching since before I met with their representative in October of 2017 in Dublin. They are now in Beta testing for a few individuals, but they have also just changed their DNA processing chip – so how that will affect things and how soon they will have matching ready to roll out the door is unknown.
  • Ancestry did a 2018 ethnicity update, integrating ethnicity more tightly with Genetic Communities, offered genetic traits and made some minor improvements this year, along with adding one questionable feature – showing your matches the location where you live as recorded in your profile. (23andMe subsequently added the same feature.) Ancestry recently said that they are promising exciting new tools for 2019, but somehow I doubt that the chromosome browser that’s been on my Christmas list for years will be forthcoming. Fingers crossed for something new and really useful. In the mean time, we can download our DNA results and upload to MyHeritage, Family Tree DNA and GedMatch for segment matching, as well as utilize Ancestry’s internal matching tools. DNA+tree matching, those green leaf shared ancestor hints, is still their strongest feature.
  • The Family Tree DNA Conference for Project Administrators will be held March 22-24 in Houston this year, and I’m hopeful that they will have new tools and announcements at that event. I’m looking forward to seeing many old friends in Houston in March.

Here’s what I know for sure about 2019 – it’s going to be an amazing year. We as a community and also as individual genealogists will be making incredible discoveries and moving the ball forward. I can hardly wait to see what quandaries I’ve solved a year from now.

What mysteries do you want to unravel?

I’d like to offer a big thank you to everyone who made 2018 wonderful and a big toast to finding lots of new ancestors and breaking down those brick walls in 2019.

Happy New Year!!!

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Disclosure

I receive a small contribution when you click on the link to one of the vendors in my articles. This does NOT increase the price you pay, but helps me to keep the lights on and this informational blog free for everyone. Please click on the links in the articles or to the vendors below if you are purchasing products or DNA testing.

Thank you so much.

Whole Genome Sequencing – Is It Ready for Prime Time?

Dante Labs is offering a whole genomes test for $199 this week as an early Black Friday special.

Please note that just as I was getting ready to push the publish button on this article, Veritas Genetics also jumped on the whole sequencing bandwagon for $199 for the first 1000 testers Nov. 19 and 20th. In this article, I discuss the Dante Labs test. I have NOT reviewed Veritas, their test nor terms, so the same cautions discussed below apply to them and any other company offering whole genome sequencing. The Veritas link is here.

Update – Veritas provides the VCF file for an additional $99, but does not provide FASTQ or BAM files, per their Tweet to me.

I have no affiliation with either company.

$199 (US) is actually a great price for a whole genome test, but before you click and purchase, there are some things you need to know about whole genome sequencing (WGS) and what it can and can’t do for you. Or maybe better stated, what you’ll have to do with your own results before you can utilize the information for genealogical purposes.

The four questions you need to ask yourself are:

  • Why do you want to consider whole genome testing?
  • What question(s) are you trying to answer?
  • What information do you seek?
  • What is your testing goal?

I’m going to say this once now, and I’ll say it again at the end of the article.

Whole genome sequencing tests are NOT A REPLACEMENT FOR GENEALOGICAL DNA TESTS for mitochondrial, Y or autosomal testing. Whole genome sequencing is not a genealogy magic bullet.

There are both pros and cons of this type of purchase, as with most everything. Whole genome tests are for the most experienced and technically savvy genetic genealogists who understand both working with genetics and this field well, who have already taken the vendors’ genealogy tests and are already in the Y, mitochondrial and autosomal comparison data bases.

If that’s you or you’re interested in medical information, you might want to consider a whole genome test.

Let’s start with some basics.

What Is Whole Genome Sequencing?

Whole Genome Sequencing will sequence most of your genome. Keep in mind that humans are more than 99% identical, so the only portions that you’ll care about either medically or genealogically are the portions that differ or tend to mutate. Comparing regions where you match everyone else tells you exactly nothing at all.

Exome Sequencing – A Subset of Whole Genome

Exome sequencing, a subset of whole genome sequencing is utilized for medical testing. The Exome is the region identified as the portions most likely to mutate and that hold medically relevant information. You can read about the benefits and challenges of exome testing here.

I have had my Exome sequenced twice, once at Helix and once at Genos, now owned by NantOmics. Currently, NantOmics does not have a customer sign-in and has acquired my DNA sequence as part of the absorption of Genos. I’ll be writing about that separately. There is always some level of consumer risk in dealing with a startup.

I wrote about Helix here. Helix sequences your Exome (plus) so that you can order a variety of DNA based or personally themed products from their marketplace, although I’m not convinced about the utility of even the legitimacy of some of the available tests, such as the “Wine Explorer.”

On the other hand, the world-class The National Geographic Society’s Genographic Project now utilizes Helix for their testing, as does Spencer Well’s company, Insitome.

You can also pay to download your Exome sequence data separately for $499.

Autosomal Testing for Genealogy

Both whole genome and Exome testing are autosomal testing, meaning that they test chromosomes 1-22 (as opposed to Y and mitochondrial DNA) but the number of autosomal locations varies vastly between the various types of tests.

The locations selected by the genealogy testing companies are a subset of both the whole genome and the Exome. The different vendors that compare your DNA for genealogy generally utilize between 600,000 and 900,000 chip-specific locations that they have selected as being inclined to mutate – meaning that we can obtain genealogically relevant information from those mutations.

Some vendors (for example, 23andMe and Ancestry) also include some medical SNPs (single nucleotide polymorphisms) on their chips, as both have formed medical research alliances with various companies.

Whole genome and Exome sequencing includes these same locations, BUT, the whole genome providers don’t compare the files to other testers nor reduce the files to the locations useful for genealogical comparisons. In other words, they don’t create upload files for you.

The following chart is not to scale, but is meant to convey the concept that the Exome is a subset of the whole genome, and the autosomal vendors’ selected SNPs, although not the same between the companies, are all subsets of the Exome and full genome.

I have not had my whole genome sequenced because I have seen no purpose for doing so, outside of curiosity.

This is NOT to imply that you shouldn’t. However, here are some things to think about.

Whole Genome Sequencing Questions

Coverage – Medical grade coverage is considered to be 30X, meaning an average of 30 scans of every targeted location in your genome. Some will have more and some will have less. This means that your DNA is scanned thirty different times to minimize errors. If a read error happens once or twice, it’s unlikely that the same error will happen several more times. You can read about coverage here and here.

Genomics Education Programme [CC BY 2.0 (https://creativecommons.org/licenses/by/2.

Here’s an example where the read length of Read 1 is 18, and the depth of the location shown in light blue is 4, meaning 4 actual reads were obtained. If the goal was 30X, then this result would be very poor. If the goal was 4X then this location is a high quality result for a 4X read.

In the above example, if the reference value, meaning the value at the light blue location for most people is T, then 4 instances of a T means you don’t have a mutation. On the other hand, if T is not the reference value, then 4 instances of T means that a mutation has occurred in that location.

Dante Labs coverage information is provided from their webpage as follows:

Other vendors coverage values will differ, but you should always know what you are purchasing.

Ownership – Who owns your data? What happens to your DNA itself (the sample) and results (the files) under normal circumstances and if the company is sold. Typically, the assets of the company, meaning your information, are included during any acquisition.

Does the company “share, lease or sell” your information as an additional revenue stream with other entities? If so, do they ask your permission each and every time? Do they perform internal medical research and then sell the results? What, if anything, is your DNA going to be used for other than the purpose for which you purchased the test? What control do you exercise over that usage?

Read the terms and conditions carefully for every vendor before purchasing.

File Delivery – Three types of files are generated during a whole genome test.

The VCF (Variant Call Format) which details your locations that are different from the reference file. A reference file is the “normal” value for humans.

A FASTQ file which includes the nucleotide sequence along with a corresponding quality score. Mutations in a messy area or that are not consistent may not be “real” and are considered false positives.

The BAM (Binary Alignment Map) file is used for Y DNA SNP alignment. The output from a BAM file is displayed in Family Tree DNA’s Big Y browser for their customers. Are these files delivered to you? If so, how? Family Tree DNA delivers their Big Y DNA BAM files as free downloads.

Typically whole genome data is too large for a download, so it is sent on a disc drive to you. Dante provides this disc for BAM and FASTQ files for 59 Euro ($69 US) plus shipping. VCF files are available free, but if you’re going to order this product, it would be a shame not to receive everything available.

Version – Discoveries are still being made to the human genome. If you thought we’re all done with that, we’re not. As new regions are mapped successfully, the addresses for the rest change, and a new genomic map is created. Think of this as street addresses and a new cluster of houses is now inserted between existing houses. All of the houses are periodically renumbered.

Today, typically results are delivered in either of two versions: hg19(GRVH37) or hg38(GRCH38). What happens when the next hg (human genome) version is released?

When you test with a vendor who uses your data for comparison as a part of a product they offer, they must realign your data so that the comparison will work for all of their customers (think Family Tree DNA and GedMatch, for example), but a vendor who only offers the testing service has no motivation to realign your output file for you. You only pay for sequencing, not for any after-the-fact services.

Platform – Multiple sequencing platforms are available, and not all platforms are entirely compatible with other competing platforms. For example, the Illumina platform and chips may or may not be compatible with the Affymetrix platform (now Thermo Fisher) and chips. Ask about chip compatibility if you have a specific usage in mind before you purchase.

Location – Where is your DNA actually being sequenced? Are you comfortable having your DNA sent to that geographic location for processing? I’m personally fine with anyplace in either the US, Canada or most of Europe, but other locations maybe not so much. I’d have to evaluate the privacy policies, applicable laws, non-citizen recourse and track record of those countries.

Last but perhaps most important, what do you want to DO with this file/information?

Utilization

What you receive from whole genome sequencing is files. What are you going to do with those files? How can you use them? What is your purpose or goal? How technically skilled are you, and how well do you understand what needs to be done to utilize those files?

A Specific Medical Question

If you have a particular question about a specific medical location, Dante allows you to ask the question as soon as you purchase, but you must know what question to ask as they note below.

You can click on their link to view their report on genetic diseases, but keep in mind, this is the disease you specifically ask about. You will very likely NOT be able to interpret this report without a genetic counselor or physician specializing in this field.

Take a look at both sample reports, here.

Health and Wellness in General

The Dante Labs Health and Wellness Report appears to be a collaborative effort with Sequencing.com and also appears to be included in the purchase price.

I uploaded both my Exome and my autosomal DNA results from the various testing companies (23andMe V3 and V4, Ancestry V1 and V2, Family Tree DNA, LivingDNA, DNA.Land) to Promethease for evaluation and there was very little difference between the health-related information returned based on my Exome data and the autosomal testing vendors. The difference is, of course, that the Exome coverage is much deeper (and therefore more reliable) because that test is a medical test, not a consumer genealogy test and more locations are covered. Whole genome testing would be more complete.

I wrote about Promethease here and here. Promethease does accept VCF files from various vendors who provide whole genome testing.

None of these tests are designed or meant for medical interpretation by non-professionals.

Medical Testing

If you plan to test with the idea that should your physician need a genetics test, you’re already ahead of the curve, don’t be so sure. It’s likely that your physician will want a genetics test using the latest technology, from their own lab, where they understand the quality measures in place as well as how the data is presented to them. They are unlikely to accept a test from any other source. I know, because I’ve already had this experience.

Genealogical Comparisons

The power of DNA testing for genealogy is comparing your data to others. Testing in isolation is not useful.

Mitochondrial DNA – I can’t tell for sure based on the sample reports, but it appears that you receive your full sequence haplogroup and probably your mutations as well from Dante. They don’t say which version of mitochondrial DNA they utilize.

However, without the ability to compare to other testers in a database, what genealogical benefit can you derive from this information?

Furthermore, mitochondrial DNA also has “versions,” and converting from an older to a newer version is anything but trivial. Haplogroups are renamed and branches sawed from one part of the mitochondrial haplotree and grafted onto another. A testing (only) vendor that does not provide comparisons has absolutely no reason to update your results and can’t be expected to do so. V17 is the current build, released in February 2016, with the earlier version history here.

Family Tree DNA is the only vendor who tests your full sequence mitochondrial DNA, compares it to other testers and updates your results when a new version is released. You can read more about this process, here and how to work with mtDNA results here.

Y DNA – Dante Labs provides BAM files, but other whole genome sequencers may not. Check before you purchase if you are interested in Y DNA. Again, you’ll need to be able to analyze the results and submit them for comparison. If you are not capable of doing that, you’ll need to pay a third party like either YFull or FGS (Full Genome Sequencing) or take the Big Y test at Family Tree DNA who has the largest Y Database worldwide and compares results.

Typically whole genome testers are looking for Y DNA SNPs, not STR values in BAM files. STR (short tandem repeat) values are the results that you receive when you purchase the 37, 67 or 111 tests at Family Tree DNA, as compared to the Big Y test which provides you with SNPs in order to resolve your haplogroup at the most granular level possible. You can read about the difference between SNPs and STRs here.

As with SNP data, you’ll need outside assistance to extract your STR information from the whole genome sequence information, none of which will be able to be compared with the testers in the Family Tree DNA data base. There is also an issue of copy-count standardization between vendors.

You can read about how to work with STR results and matches here and Big Y results here.

Autosomal DNA – None of the major providers that accept transfers (MyHeritage, Family Tree DNA, GedMatch) accept whole genome files. You would need to find a methodology of reducing the files from the whole genome to the autosomal SNPs accepted by the various vendors. If the vendors adopt the digital signature technology recently proposed in this paper by Yaniv Erlich et al to prevent “spoofed files,” modified files won’t be accepted by vendors.

Summary

Whole genome testing, in general, will and won’t provide you with the following:

Desired Feature Whole Genome Testing
Mitochondrial DNA Presumed full haplogroup and mutations provided, but no ability for comparison to other testers. Upload to Family Tree DNA, the only vendor doing comparisons not available.
Y DNA Presume Y chromosome mostly covered, but limited ability for comparison to other testers for either SNPs or STRs. Must utilize either YFull or FGS for SNP/STR analysis. Upload to Family Tree DNA, the vendor with the largest data base not available when testing elsewhere.
Autosomal DNA for genealogy Presume all SNPs covered, but file output needs to be reduced to SNPs offered/processed by vendors accepting transfers (Family Tree DNA, MyHeritage, GedMatch) and converted to their file formats. Modified files may not be accepted in the future.
Medical (consumer interest) Accuracy is a factor of targeted coverage rate and depth of actual reads. Whole genome vendors may or may not provide any analysis or reports. Dante does but for limited number of conditions. Promethease accepts VCF files from vendors and provides more.
Medical (physician accepted) Physician is likely to order a medical genetics test through their own institution. Physicians may not be willing to risk a misdiagnosis due to a factor outside of their control such as an incompatible human genome version.
Files VCF, FASTQ and BAM may or may not be included with results, and may or may not be free.
Coverage Coverage and depth may or may not be adequate. Multiple extractions (from multiple samples) may or may not be included with the initial purchase (if needed) or may be limited. Ask.
Updates Vendors who offer sequencing as a part of a products that include comparison to other testers will update your results version to the current reference version, such as hg38 and mitochondrial V17. Others do not, nor can they be expected to provide that service.
Version Inquire as to the human genome (hg) version or versions available to you, and which version(s) are acceptable to the third party vendors you wish to utilize. When the next version of the human genome is released, your file will no longer be compatible because WGS vendors are offering sequencing only, not results comparisons to databases for genealogy.
Ownership/Usage Who owns your sample? What will it be utilized for, other than the service you ordered, by whom and for what purposes? Will you we able to authorize or decline each usage?
Location Where geographically is your DNA actually being sequenced and stored? What happens to your actual DNA sample itself and the resulting files? This may not be the location where you return your swab kit.

The Question – Will I Order?

The bottom line is that if you are a genealogist, seeking genetic information for genealogical purposes, you’re much better off to test with the standard and well know genealogy vendors who offer compatibility and comparisons to other testers.

If you are a pioneer in this field, have the technical ability required to make use of a whole genome test and are willing to push the envelope, then perhaps whole genome sequencing is for you.

I am considering ordering the Dante Labs whole genome test out of simple curiosity and to upload to Promethease to determine if the whole genome test provides me with something potentially medically relevant (positive or negative) that autosomal and Exome testing did not.

I’m truly undecided. Somehow, I’m having trouble parting with the $199 plus $69 (hard drive delivery by request when ordering) plus shipping for this limited functionality. If I was a novice genetic genealogist or was not a technology expert, I would definitely NOT order this test for the reasons mentioned above.

A whole genome test is not in any way a genealogical replacement for a full sequence mitochondrial test, a Y STR test, a Y SNP test or an autosomal test along with respective comparison(s) in the data bases of vendors who don’t allow uploads for these various functions.

The simple fact that 30X whole genome testing is available for $199 plus $69 plus shipping is amazing, given that 15 years ago that same test cost 2.7 billion dollars. However, it’s still not the magic bullet for genealogy – at least, not yet.

Today, the necessary integration simply doesn’t exist. You pay the genealogy vendors not just for the basic sequencing, but for the additional matching and maintenance of their data bases, not to mention the upgrading of your sequence as needed over time.

If I had to choose between spending the money for the WGS test or taking the genealogy tests, hands down, I’d take the genealogy tests because of the comparisons available. Comparison and collaboration is absolutely crucial for genealogy. A raw data file buys me nothing genealogically.

If I had not previously taken an Exome test, I would order this test in order to obtain the free Dante Health and Wellness Report which provides limited reporting and to upload my raw data file to Promethease. The price is certainly right.

However, keep in mind that once you view health information, you cannot un-see it, so be sure you do really want to know.

What do you plan to do? Are you going to order a whole genome test?

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Standard Disclosure

This standard disclosure appears at the bottom of every article in compliance with the FTC Guidelines.

I provide Personalized DNA Reports for Y and mitochondrial DNA results for people who have tested through Family Tree DNA. I provide Quick Consults for DNA questions for people who have tested with any vendor. I would welcome the opportunity to provide one of these services for you.

Hot links are provided to Family Tree DNA, where appropriate. If you wish to purchase one of their products, and you click through one of the links in an article to Family Tree DNA, or on the sidebar of this blog, I receive a small contribution if you make a purchase. Clicking through the link does not affect the price you pay. This affiliate relationship helps to keep this publication, with more than 900 articles about all aspects of genetic genealogy, free for everyone.

I do not accept sponsorship for this blog, nor do I write paid articles, nor do I accept contributions of any type from any vendor in order to review any product, etc. In fact, I pay a premium price to prevent ads from appearing on this blog.

When reviewing products, in most cases, I pay the same price and order in the same way as any other consumer. If not, I state very clearly in the article any special consideration received. In other words, you are reading my opinions as a long-time consumer and consultant in the genetic genealogy field.

I will never link to a product about which I have reservations or qualms, either about the product or about the company offering the product. I only recommend products that I use myself and bring value to the genetic genealogy community. If you wonder why there aren’t more links, that’s why and that’s my commitment to you.

Thank you for your readership, your ongoing support and for purchasing through the affiliate link if you are interested in making a purchase at Family Tree DNA, or one of the affiliate links below:

Affiliate links are limited to:

DNA.Land

DNA.Land first launched in October of 2015, a free upload site whose goal is to encourage sharing to enable scientists to make new discoveries including the initiative to understand what is needed for a cure for breast cancer by 2020.

Their purpose, as stated by DNA.Land in their FAQ:

DNA.Land is a place where you can learn more about your genome while enabling scientists to make new genetic discoveries for the benefit of humanity. Our goal is to help members to interpret their data and to enable their contribution to research.

DNA.Land has invested a lot of effort into providing tools for genetic genealogists in order to encourage them to upload their autosomal DNA testing results to DNA.Land and participate in research in exchange for having access to their tools.

Let’s step through the process and take a look at their offerings.

If you’re interested in participating, the first thing to do is to register and the next step is the consent process.

Consent

If you are considering participation, or uploading your DNA to utilize their ethnicity or matching services, you must sign their consent form. Needless to say, you need to fully read the consent form before clicking to authorize, at DNA.Land and anyplace else.

Please note that you can click on any image to enlarge.

Upload Your File

After you click to approve and continue, you’ll be asked to select a file to upload. I chose Family Tree DNA Build 37.

Research Questions

Given that the focus of DNA.Land is medical research, you’ll be asked questions about yourself and your ancestry, such as your birthdate, as well as that of your parents.

I joined the Breast Cancer research and authorized researchers to contact me.

You are then asked, “Is this file your file?” DNA.Land wants to be absolutely sure you are providing information for your own file, and not someone else’s.

DNA.Land then asks questions related to your family and breast cancer. I answered the questions, agreed to be contacted if there are questions and joined the study.

You’ll answer questions about whether your parent, full siblings or children have been diagnosed with breast cancer, as well as questions about yourself.

I was excited to see that I was the 7,456th person to join the breast cancer initiative, but then I realized that their goal is 25,000 by the end of 2017. They have a LONG way to go. Please consider joining.

Your Personal Page

Your personal page includes your file status, the research projects in which you are participating as well as reports available.

Your file status is shown at the bottom of the page, including links to learn more.

About Imputation

DNA.Land was the first vendor to attempt imputation. I wrote about imputation in the article, Concepts – Imputation. I also wrote about matching with a vendor who utilizes imputation in the article Imputation Matching Comparison.

Imputation affects your matches, segment sizes and the quality of those matches. If you’re not familiar with imputation, I would strongly suggest reading these articles now.

While I’m incredibly supportive of the breast cancer and research initiatives, I’m less excited about the accuracy of imputation relative to genetic genealogy. Let’s take a look.

My Reports

Now that I’m done with setup and questions, I’m ready to view information about my own DNA results according to DNA.Land. Remember that these results include imputed information, meaning data that was imputed to be mine in regions not tested based on my DNA in regions that have been tested. My Family Tree DNA file that I uploaded held over 700,000 tested locations, and DNA.Land imputes another 38 million locations based on the 700,000 that were actually tested.

You can select from various My Reports options:

  • Find Relatives
  • Find Relatives of Relatives
  • Ancestry Report
  • Trait Prediction Report

Let’s look at each one.

Find Relatives

As of today, just over 70,000 individuals have uploaded, an increase of 10,000 in just under two months, so the site is rapidly growing.

The first page is DNA Relationship Matches. The match below is my closest match to cousin, Karen. I wrote about dissecting this match in the article Imputation Matching Comparison.

You can show or hide the chromosome table at far right. Segments are divided into recent and ancient based on the segment size. I’m not sure I would have used the term “ancient,” but what DNA.Land is trying to convey is that more often, smaller segments are older than larger segments.

I have 11 High Certainty matches and 1 speculative.

The information page explains more. Click on the “Learn more about the report” link in the upper left hand corner, which displays the following example information.

All reported segments are 3.00 cM or larger.

Very beneficially, my closest match, Karen, showed her GedMatch kit number as her middle name. I utilized her file at GedMatch and her results at DNA.Land to compare raw data file matching and imputed file matching. You can read about the findings in the article, Imputation Matching Comparison.

Based on imputed matching, I’m not sure that today I would have much confidence in matches to the relatives of relatives, but let’s take a look anyway.

Find Relatives of Relatives

Relative of relatives is a big confusing.  Think if it as an alternate to a chromosome browser.  Here’s what their information page says about this feature.

This is a bit confusing. The “via” relative is the person on your match report.

The first person listed, or the “endpoint” relative is the person related to them.

The intersection is the set of intersecting matching segments between you, your match and their match that (apparently) also matches you, or they would not be on this report.

Here’s a Relatives of Relatives match with my strongest match, Karen.

The problem is that the person shown as Karen’s match, Shelley, is not shown as my match.  The common matching segments between the three of us, shown above and below, are very small.  Even though Shelley is a match to Karen, Shelley apparently only matches me on smaller segments, not large enough to pass the DNA.Land threshold for a match.

The problem is that all of the above matching and triangulating segments above are imputed segments and don’t show up as legitimate matches at GedMatch between me and Karen, so they can’t be a valid three way match between me, Karen and Shelley.

In other words, these aren’t valid matches at all, even before the discussion about whether they are identical by descent, chance or population.  Therefore, these have to be matches on imputed regions, not through actual testing.

The certainty field is also confusing.  I initially though that the “high” certainty pertained to the three way match certainty, but it doesn’t.  Certainty means the certainty of the match between your match (the via relative) and the endpoint (their match) and has nothing to do with the certainty of the segments matching the three of you being relevant.

If you’d like to utilize this information, please read the information pages VERY CAREFULLY and be sure you understand what the information, is, and isn’t, telling you.

Ancestry Report (Ethnicity)

The Ancestry report is DNA.Land’s ethnicity report.

Looking at the map, it’s difficult to compare the DNA.Land results to other vendors, because they have Scandinavia divided into half, with the westernmost part of Scandinavia included in their Northwest Europe orange grouping, the light green designated as Finnish with the olive green as North Slavic. Other vendors include Norway and all of Sweden as part of Scandinavia.

One nice thing is that the population reference locations are shown on the map below, even for non-matching reference groups.

In my case, DNA.Land missed my Native American entirely.

The chart below represents my known and proven genealogy as compared to the DNA.land ethnicity results.

You can see how DNA.Land stacks up against the rest of the vendors, below.

Trait Prediction Report

The trait report requires an additional consent form. In essence, DNA.Land wants to make sure you really want to see your traits, that you understand what you are going to see and that you understand how traits are calculated and displayed.

DNA.land offers several traits you can select from.

But there’s a hitch.

Before you can see your traits, you get to answer a survey. In all fairness, DNA.Land’s purpose is medical research, and the reports participants receive are free.

My eye color is accurate, BUT, I also just told them that my eye color is dark brown during the questions. Not terribly confidence inspiring – but my confidence increased  after reviewing all of the information they provided about the science behind my actual trait prediction.

The eye color map, above, is something unique I haven’t seen elsewhere. I find this kind of information quite interesting.

Even though I did provide DNA.Land with the “brown eyes” answer, this chart makes me feel much better, because they shared the science behind my result with me. Therefore, I now feel much better, because, based on the science, it’s apparent that they didn’t just parrot my result back to me.

There is also a “what if my result is wrong” link. After all, science is all about continuing to learn and to think we know everything there is to know about genetics is foolhearty.

Yea, I like this a LOT!

If you’d like to read more about how genetic research takes place, read the interesting article titled Is there a Firefox Gene? Yes, that’s the Firefox browser, and yes, this is a real study. Take a look. It’s really quite interesting and written in plain English.

Summary

DNA.Land has a different purpose than other DNA matching and ethnicity sites. As a nonprofit, DNA.Land offers their matching and ethnicity services as an enticement to genetic genealogists who have paid to test elsewhere to upload their results to DNA.land and in doing so, to participate in medical research.

DNA.Land is absolutely up front about their mission. The features are “complimentary,” so to speak, meant to be enticements to consumers to participate and contribute their DNA results.

Given that, it’s difficult to be terribly upset with DNA.Land’s features and services.

DNA.Land has a nice user interface and some nice display features. Their eye color mapping isn’t found elsewhere, and other similar features would make great teaching tools. Their help pages are informative and educational.

Imputation concerns me. Imputation for medical research doesn’t directly affect me today, although it may someday, given that imputed data is used for research.

Imputed data does affect your results at Promethease if you choose to utilize your imputed results as input for any application that reports your academic and/or medical mutations. You can read about that in the article, Imputation Analysis Using Promethease.

Imputation affects matching for genetic genealogy negatively. While I didn’t discuss matching quality in this article, I did in the article Imputation Matching Comparison, which I would encourage you to read if you are attempting to utilize the DNA.Land matching function seriously for genealogy. I would encourage genetic genealogists to simply match at the vendor where they tested, or at Family Tree DNA which accepts uploads (Ancestry V1, V2 and 23andMe V3, V4) from other vendors, or at GedMatch for serious match analysis.

My suggestion to DNA.Land for matching would be to eliminate the smaller segments entirely, especially if they are a result of imputation and not actual matching DNA segments. In my limited experiment, DNA.Land seemed to do relatively well on matching and utilizing larger segments.

Ethnicity results at DNA.Land, called Ancestry Results, are divided oddly, with Northwestern Europe including all of the British Isles, western Scandinavia along with the northwest quadrant of continental Europe. This division makes it extremely difficult to compare to other vendors’ results.

DNA.Land seems to report an unrealistic amount of Southern European, but again, it’s somewhat difficult to tell where the dividing line occurs. It would be easier if their ethnicity map were overlayed on a current map of Europe showing country boundaries. DNA.Land missed my Native entirely.

It would be interesting to know how much of the ethnicity results are calculated on actual DNA and how much through imputation. Ethnicity results tend to be dicey enough in the industry as a whole without adding the uncertainty of imputation on top. Having said that, given how popular ethnicity testing has become, offering another ethnicity opinion is probably a large draw for attracting people to upload and participate in research at DNA.Land.

Some of the trait information is quite interesting and new traits will probably be equally so, although I wonder how much of that information is imputed as well. In other words, I don’t know if the results are actually “mine” through testing or could be in error. The good news is that DNA.Land provides the genetic locations where the trait analysis is compiled, allowing you to utilize a service like Promethease which provides the ability in some cases to confirm imputed data if you upload your actual tested files from testing vendors.

For all results, I would very much like to see a toggle where you can toggle between actual match results and match results derived from imputation.

I would also like to see some research about the accuracy of imputation as compared to non-imputed results. Clearly this would be available through research efforts like my own at Promethease, exome and full genome sequencing.

In a nutshell, DNA.Land provides an interesting free service so long as you don’t want to take the results terribly seriously for genealogy research. If any of the results are important or you want to depend upon them for accuracy, verify elsewhere with actual tested data.

It’s important to remember at DNA.Land that their real goal isn’t to provide a product or to compete with the testing vendors. Their features are a “thank you” or enticement for consumers to contribute their autosomal data for medical research, some of which may be “for profit.”  Companies aren’t going to participate in research initiatives that don’t hold the potential for profit.

I really didn’t need an enticement, but I’m grateful nonetheless.

Additionally, DNA.Land has provided an important first foray into imputation and allowed us to compare imputed data with tested data. I know that wasn’t their goal, but I’m glad to have the opportunity to learn and work with real life examples. My own. I would encourage you to do the same.

Be Part of the Cure

The last thing I have to say is that I truly hope and pray that the Breast Cancer Deadline shown as 2020 is a real and achievable goal.

I welcome the opportunity for anything I can to do help eliminate that horrific scourge that has affected so many women. Breast cancer has taken the lives of my family members and friends, as I’m sure it has yours, and I would like nothing better than to participate in some small way in wiping it off the face of the earth. DNA.Land is one way you can help, and it costs you absolutely nothing.

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Standard Disclosure

This standard disclosure appears at the bottom of every article in compliance with the FTC Guidelines.

Hot links are provided to Family Tree DNA, where appropriate. If you wish to purchase one of their products, and you click through one of the links in an article to Family Tree DNA, or on the sidebar of this blog, I receive a small contribution if you make a purchase. Clicking through the link does not affect the price you pay. This affiliate relationship helps to keep this publication, with more than 850 articles about all aspects of genetic genealogy, free for everyone.

I do not accept sponsorship for this blog, nor do I write paid articles, nor do I accept contributions of any type from any vendor in order to review any product, etc. In fact, I pay a premium price to prevent ads from appearing on this blog.

When reviewing products, in most cases, I pay the same price and order in the same way as any other consumer. If not, I state very clearly in the article any special consideration received. In other words, you are reading my opinions as a long-time consumer and consultant in the genetic genealogy field.

I will never link to a product about which I have reservations or qualms, either about the product or about the company offering the product. I only recommend products that I use myself and bring value to the genetic genealogy community. If you wonder why there aren’t more links, that’s why and that’s my commitment to you.

Thank you for your readership, your ongoing support and for purchasing through the affiliate link if you are interested in making a purchase at Family Tree DNA.

Imputation Analysis Utilizing Promethease

We know in the genetics industry that imputation is either coming or already here for genetic genealogy. I recently wrote two articles, here and here, explaining imputation and its (apparent) effects on matching – or at least the differences between vendors who do and don’t utilize imputation on the segments that are set forth as matches.

I will be writing shortly about my experience utilizing DNA.Land, a vendor who encourages testers to upload their files to be shared with medical researchers. In return, DNA.Land provides matching information and ethnicity – but they do impute results that you don’t have based on“typical” DNA that is generally inherited with the DNA you do have.

Aside from my own curiosity and interest in health, I have been attempting to determine the relative accuracy of imputation.

Promethease is a third party site that provides consumers who upload their autosomal DNA files with published information about their SNPs, mutations, either bad, good or neither, meaning just information. This makes Promethease the perfect avenue for comparing the accuracy of the imputed data provided by DNA.Land compared against the data provided by Promethease generated from files from vendors who do not impute.

Even better, I can directly compare the autosomal file from Family Tree DNA that I uploaded to DNA.Land with my resulting DNA.Land file after DNA.Land imputed another 38 million locations. I can also compare the DNA.Land results to an extensive exome test that provided results for some 50 million locations.

Uploading all of the files from various testing vendors separately to Promethease allows me to see which of the mutations imputed by DNA.Land are accurate when compared to actual DNA tests, and if the imputed mutations are accurate when the same location was tested by any vendor.

In addition to the typical genetic genealogy vendors, I’ve also had my DNA exome sequenced, which includes the 50 million locations in humans most likely to mutate.  This means those locations should be the locations most likely to be imputed by DNA.Land.

Finally, at Promethease, I can combine my results from all the vendors where I actually tested to provide the greatest coverage of actually tested locations, and then compare to DNA.Land – providing the most comprehensive comparison.

I will utilize the testing vendors’ actual results to check the DNA.Land imputed results.

Let’s see what the results produce.

The Test Process

The method I used for this comparison was to upload my Family Tree DNA autosomal raw data file to DNA.Land. DNA.Land then took the 700,000+ locations that I did test for at Family Tree DNA, and imputed more than 38 million additional locations, raising my tested and imputed number of locations to about 39 million.

Then, I downloaded and uploaded my huge DNA.Land file, utilizing the Promethease instructions.

In order to do a comparison against the imputed data that DNA.Land provided, I uploaded files from the following vendors individually, one at a time, to Promethease to see which versions of the files provided which results – meaning which mutations the files produced by actual testing at vendors could confirm in the DNA.Land imputed results.

  • DNA.Land (imputed)
  • Genos – Exome testing of 50 million medically relevant locations
  • Ancestry V1 test
  • Ancestry V2 test
  • Family Tree DNA
  • 23andMe V3 test
  • 23andMe V4 test
  • Combined file of all non-imputed vendor files

Promethease provides a wonderful feature that enables users to combine multiple vendors’ files into one run. As a final test, I combined all of my non-imputed files into one run in order to compare all of my non-imputed results, together, with DNA.Land’s imputed results.

Promethease provides results that fall into 3 categories:

  • Bad – red
  • Good – green
  • Grey – “not set” – neither bad nor good, just information

Promethease does not provide diagnoses of any form, just information from the published literature about various mutations and genetic markers and what has been found in research, with links to the sources through SNPedia.

Results

I compiled the following chart with the results of each individual file, plus a combined file made up of all of the non-imputed files.

The results are quite interesting.

The combined run that included all of the vendors files except for DNA.Land provided more “bad” results than the imputed DNA.Land file. 

I expected that the Genos exome test would have covered all of the locations tested by the three genetic genealogy vendors, but clearly not, given that the combined run provides more results than the Genos exome run by itself. In fact, the total locations reported is 80,607 for the combined run and the Genos run alone was only 45,595.

DNA.Land only imputed 34,743 locations that returned results.

Comparison for Accuracy

Now, the question is whether the DNA.Land imputed results are accurate.

Due to the sheer number of results, I focused only on the “bad” results, the ones that would be most concerning, to get an idea of how many of the DNA.Land results were tested in the original uploaded file (from FTDNA) and how many were imputed. Of the imputed locations, I determined how many are accurate by comparing the DNA.Land results to the combined testing results. My hope, is, of course, that most of the locations found in the DNA.Land imputed file are also to be found in one of the files tested at the vendors, and therefore covered in the combined file run.

I combined my results from the following 3 runs into a common spreadsheet, color coding each result differently:

  • First, I wanted to see the locations reported as “bad” that were actually tested at FTDNA. By comparing the FTDNA locations with the DNA.Land imputed file, we know that DNA.Land was NOT imputing those locations, and conversely, that they WERE imputing the rest of the locations.
  • Second, I wanted to know if locations imputed by DNA.Land and reported as “bad” had been tested by any testing company, and if DNA.Land’s imputation was accurate as compared to an actual test.

You can read more about how Promethease reports results, here.

I’m showing two results in the spreadsheet example, below.

White row=FTDNA test result
Yellow row =DNA.Land result
Blue row=combined test result

These two examples show two mutations that are ranked as “bad” for the same condition. This result really only tells me that I metabolize some things slower than other people. Reading the fine print tells me this as well:

The proportion of slow and rapid metabolizers is known to differ between different ethnic populations. In general, the slow metabolizer phenotype is most prevalent (>80%) in Northern Africans and Scandinavians, and lowest (5%) in Canadian Eskimos and Japanese. Intermediate frequencies are seen in Chinese populations (around 20% slow metabolizers), whereas 40 – 60% of African-Americans and most non-Scandinavian Caucasians are slow metabolizers.[PMID 16416399]

Many of you are probably slow metabolizers too.

I used this example to illustrate that not everything that is “bad” is going to keep you awake at night.

The first mutation, gs140 is found in the DNA.Land file, but there is no corresponding white row, representing the original Family Tree DNA report, meaning that DNA.Land imputed the result. GS140 is, however, tested by some vendor in the combined file. The results do match (verified by actually comparing the results individually) and therefore, the DNA.Land imputation was accurate as noted in the DNA.Land Analysis column at far right.

In the second example, gs154 is reported by DNA.Land, but since it’s also reported by Family Tree DNA in the white row, we know that this value was NOT imputed by DNA.Land, because this was part of the originally uploaded file. Therefore, in the Analysis column, I labeled this result as “tested at FTDNA.”

Analysis

I analyzed each of the rows of “bad” results found in the DNA.Land file by comparing them first to the FTDNA file and then the Combined file. In some cases, I needed to return to the various vendor results to see which vendor had done the testing on a specific location in order to verify the result from the individual run.

So, how did DNA.Land do with imputing data as compared with actual tested results?

# Results % Comment
Tested, not Imputed 171 38.6 This “bad” location was tested at FTDNA and uploaded, so we know it was reported accurately at DNA.Land and not imputed.
Total Imputed* 272 61.4 Meaning total of “bad” results not tested at FTDNA, so not uploaded to DNA.Land, therefore imputed.
Imputed Correctly 259 95.22 This result was verified to match a tested location in the combined run.
Imputed, but not tested elsewhere 6 2.21 Accuracy cannot be confirmed.
Conflict 3 1.10 DNA.Land results cannot be verified due to an error of some sort – two of these three are probably accurate.
Imputed Incorrectly 4 1.47 Confirmed by the combined run where the location was actually tested at multiple vendor(s).
Not reported, and should have been 1 0.37 4 other vendor tests showed this mutation, including FTDNA which was uploaded to DNA.Land. Therefore these locations should have been reported by the DNA.Land file.

*The total number of “bad” results was 443, 171 that were tested and 272 that were imputed. Note that the percentages of imputations shown below the “Total Imputed” number of 272 are calculated based on the number of locations imputed, not on the total number of locations reported.

Concerns, Conflicts and Errors

It’s worth noting that my highest imputed “bad” risk from DNA.Land was not tested elsewhere, so cannot be verified, which concerns me.

On the three results where a conflict exists, all 3 locations were tested at multiple other vendors, and the results at the other vendors where the results were actually tested show different results from each other, which means that the DNA.Land result cannot be verified as accurate. Clearly, an error exists in at least one of the other tests.

In one conflict case, this error has occurred at 23andMe on either their V3 or V4 chip, where the results do not match each other.

In a second conflict case, two of the other vendors agree and the DNA.Land imputation is likely accurate, as it matches 2 of the three other vendor tests.

In the third conflict case, the Ancestry V2 test confirms one of the 23andMe results, which matches the DNA.Land results, so the DNA.Land result is likely accurate.

Of the 4 results that were confirmed to be imputed incorrectly, all locations were tested at multiple vendors. In two cases, the location was confirmed on two other tests and in the other two cases, the location was tested at three vendors. The testing vendor’s results all matched each other.

Summary

Overall, given the problems found with both DNA.Land and MyHeritage, who both impute, relative to genetic genealogy matching, I was surprised to find that the DNA.Land imputed health results were relatively accurate.

I expected the locations reported in the FTDNA file to be reported accurately by DNA.Land, because that data was provided to them. In one case, it was not.

Of the 272 “bad” results imputed, 259, or 95.22% could be verified as accurate.

Six could not be verified, and three were in conflict, but of those, it’s likely that two of the three were imputed accurately by DNA.Land. The third can’t be verified. This totals 3.31% of the imputed results that are ambiguous.

Only 1.47% were imputed incorrectly. If you add the .37% for the location that was not reported and should have been, and make the leap of assumption that the one of three in conflict is in error, DNA.Land is still just over a 2% confirmed error rate.

I can see why Illumina would represent to the vendors that imputation technology is “very accurate.” “Very” of course is relative, pardon the pun, in genetic genealogy, to how well matching occurs, not only when the new GSA chip is compared to another GSA chip, but when the new GSA version is compared to the older OmniExpress version. For backards compatibility between the chip versions, imputation must be utilized. Thanks a lot Illumina (said in my teenage sarcastic voice).

Since DNA.Land accepts files from all the vendors on all chips, for DNA.Land to be able to compare all locations in all vendors’ files against each other, the “missing” data in each file must be imputed. MyHeritage is doing something similar (having hired one of the DNA.Land developers), and both vendors have problems with genetic genealogy matching.

This begs the question of why the matching is demonstrably so poor for genetic genealogy. I’ve written about this phenomenon here, Kitty Cooper wrote about it here and Leah Larkin here.

Based on this comparison, each individual DNA.Land imputed file would contain about a 2% error rate of incorrectly imputed data, assuming the error rate is the same across the entire file, so a combined total of 4% for two individuals, if you’re just looking at individual SNPs. Perhaps entire segments are being imputed incorrectly, given that we know that DNA is inherited in segments. If that is the case, and these individual SNPs are simply small parts of entire segments that are imputed incorrectly, they might account for an equal number of false positive matches. In other words, if 10 segments are imputed incorrectly for me, that’s 10 segments reporting false positive matches I’ll have when paired against anyone who receives the same imputed data. However, that doesn’t explain the matches that are legitimate (on tested segments) and aren’t found by the imputing vendors, and it doesn’t explain an erroneous match rate that appears to be significantly higher than the 2-4% per cent found in this comparison.

I’ll be writing about the DNA.Land matching comparison experience shortly.

I would strongly prefer that medical research be performed on fully tested individuals. I realize that the cost of encouraging consumers to upload their data, and then imputing additional information is much less expensive than actual testing. However, accuracy is an issue and a 2% error rare, if someone is dealing with life-saving and life-threatening research could be a huge margin of error, from the beginning of the project, based on faulty imputation – which could be eliminated by simply testing people. This seems like an unnecessary risk and faulty research just waiting to happen. This error rate is on top of the actual sequencing error rate, but sequencing errors will be found in different locations in individuals, not on the same imputed segment assigned to multiple people in population groups. Imputation errors could be cumulative in one location, appearing as a hot spot when in reality, it’s an imputation error.

As related to genetic genealogy, I don’t think imputation and genetic genealogy are good bedfellows. DNA.Land’s matching was even worse when it was initially introduced, which is one reason I’ve waited so long to upload and write about the service.

Unfortunately, with Illumina obsoleting the OmniExpress chip, we’re not going to have a choice, sooner than later. All vendors who utilized the OmniExpress chip are being forced off, either onto the GSA chip or to an Exome or full sequence chip. The cost of sequencing for anything other than the GSA chip is simply more than the genetic genealogy market will stand, not to mention even larger compatibility issues. My Genos Exome test cost $499 just a few months ago and still sells for that price today.

The good news is that utilizing imputation, we will still receive matches, just less accurate matches when comparing the new chip to older versions, and when using imputation.

New testers will never know the difference. Testers not paying close attention won’t notice or won’t realize either. That leaves the rest of us “old timers” who want increased accuracy and specification, not less, flapping in the wind along with the vendors who don’t sell our test results into the medical arena and have no reason to move to the new GSA platform other than Illumina obsoleting the OmniExpress chip.

Like I said, thanks Illumina.

Imputation Matching Comparison

In a future article, I’ll be writing about the process of uploading files to DNA.Land and the user experience, but in this article, I want to discuss only one topic, and that’s the results of imputation as it affects matching for genetic genealogy. DNA.Land is one of three companies known positively to be using imputation (DNA.Land, MyHeritage and LivingDNA), and one of two that allows transfers and does matching for genealogy

This is the second in a series of three articles about imputation.

Imputation, discussed in the article, Concepts – Imputation, is the process whereby your DNA that is tested is then “expanded” by inferring results you don’t have, meaning locations that haven’t been tested, by using information from results you do have. Vendors have no choice in this matter, as Illumina, the chip maker of the DNA chip widely utilized in the genetic genealogy marketspace has obsoleted the prior chip and moved to a new chip with only about 20% overlap in the locations previously tested. Imputation is the methodology utilized to attempt to bridge the gap between the two chips for genetic genealogy matching and ethnicity predications.

Imputation is built upon two premises:

1 – that DNA locations are inherited together

2 – that people from common populations share a significant amount of the same DNA

An example of imputation that DNA.Land provides is the following sentence.

I saw a blue ca_ on your head.

There are several letters that are more likely that others to be found in the blank and some words would be more likely to be found in this sentence than others.

A less intuitive sentence might be:

I saw a blue ca_ yesterday.

DNA.Land doesn’t perform DNA testing, but instead takes a file that you upload from a testing vendor that has around 700,000 locations and imputes another 38.3 million variants, or locations, based on what other people carry in neighboring locations. These numbers are found in the SNPedia instructions for uploading DNA.Land information to their system for usage with Promethease.

I originally wrote about Promethease here, and I’ll be publishing an updated article shortly.

In this article, I want to see how imputation affects matching between people for genetic genealogy purposes.

Genetic Genealogy Matching

In order to be able to do an apples to apples comparison, I uploaded my Family Tree DNA autosomal file to DNA.Land.

DNA.Land then processed my file, imputed additional values, then showed me my matches to other people who have also uploaded and had additional locations imputed.

DNA.Land has just over 60,000 uploads in their data base today. Of those, I match 11 at a high confidence level and one at a speculative level.

My best match, meaning my closest match, Karen, just happened to have used her GedMatch kit number for her middle name. Smart lady!

Karen’s GedMatch number provided me with the opportunity to compare our actual match information at DNA.Land, then also at GedMatch, then compare the two different match results in order to see how much of our matching was “real” from portions of our tested kits that actually match, and what portion of our DNA matches as a result of the DNA.Land imputation.

At DNA.Land, your match information is presented with the following information:

  • Relationship degree – meaning estimated relationship
  • # shared segments – although many of these are extremely small
  • Total shared cM
  • Total recent shared length in cM
  • Longest recent shared segment in cM
  • Relationship likelihood graph
  • Shared segments plotted on chromosome display
  • Shared segments in a table

Please note that you can click on any graphic to enlarge.

DNA.Land provides what they believe to be an accurate estimate of recent and anciently shared SNA segments.

The match table is a dropdown underneath the chromosome graphic at far right:

For this experiment, I copied the information from the match table and dropped it into a spreadsheet.

DNALand Match Locations

My match information is shown at DNA.Land with Karen as follows:

Matching segments are identified by DNA.Land as either recent or ancient, which I find to be over-simplified at best and misleading or inaccurate at worst. I guess it depends on how you perceive recent and ancient. I think they are trying to convey the concept that larger segments tend to me more recent, and smaller segments tend to be older, but ancient in the genetics field often refers to DNA extracted from exhumed burials from thousands of years ago.  Furthermore, smaller segments can be descended from the same ancestor as larger segments.

GedMatch Match

Since Karen so kindly provided her GedMatch kit number, I signed in to GedMatch and did a one-to-one match with this same kit.

Since all of the segments are 3 cM and over at DNA.Land, I utilized a GedMatch threshold of 3 cM and dropped the SNP count to 100, since a SNP count of 300 gave me few matches. For this comparison, I wanted to see all my matches to Karen, no matter how few SNPs are involved, in an attempt to obtain results similar to DNA.Land. I normally would not drop either of these thresholds this low. My typical minimum is 5cM and 500 SNPs, and even if I drop to 3cM, I still maintain the 500 SNP threshold.

Let’s see how the data from GedMatch and DNA.Land compares.

In my spreadsheet, below, I pasted the segment match information from DNA.Land in the first 5 columns with a red header. Note that DNA.Land does not provide the number of shared SNPs.

At right, I pasted the match information from GedMatch, with a green header. We know that GedMatch has a history of accurately comparing segments, and we can do a cross platform comparison. I originally uploaded my FTDNA file to DNA.Land and Karen uploaded an Ancestry file. Those are the two files I compared at GedMatch, because the same actual matching locations are being compared at both vendors, DNA.Land (in addition to imputed regions) and GedMatch.

I then copied the matching segments from GedMatch (3cM, 100 SNPs threshold) and placed them in the middle columns in the same row where they matched corresponding DNA.Land segments. If any portion of the two vendors segments overlapped, I copied them as a match, although two are small and partial and one is almost negligible. As you can see, there are only 10 segments with any overlap at all in the center section. Please note that I am NOT suggesting these are valid or real matches.  At this point, it’s only a math/match exercise, not an analysis.

The match comparison column (yellow header) is where I commented on the match itself. In some cases, the lack of the number of SNPs at DNA.Land was detrimental to understanding which vendor was a higher match. Therefore, when possible, I marked the higher vendor in the Match Comparison column with the color of their corresponding header.

Analysis

Frankly, I was shocked at the lack of matching between GedMatch and DNA.Land. Trying to understand the discrepancy, I decided to look at the matches between Karen, who has been very helpful, and me at other vendors.

I then looked at our matches at Ancestry, 23andMe, MyHeritage and at Family Tree DNA.

The best comparison would be at Family Tree DNA where Karen loaded her Ancestry file.  Therefore, I’m comparing apples to apples, meaning equivalent to the comparison at GedMatch and DNA.Land (before imputation).

It’s impossible to tell much without a chromosome browser at Ancestry, especially after Timber processing which reduces matching DNA.

DNA.Land categorized my match to Karen as “high certainty.” My match with Karen appears to be a valid match based on the longest segment(s) of approximately 30cM on chromosome 8.

  • Of the 4 segments that DNA.Land identifies as “recent” matches, 2 are not reflected at all in the GedMatch or Family Tree DNA matching, suggesting that these regions were imputed entirely, and incorrectly.
  • Of the 4 segments that DNA.Land identifies as “recent” matches, the 2 on chromosome 8 are actually one segment that imputation apparently divided. According to DNA.LAND, imputation can increase the number of matching segments. I don’t think it should break existing segments, meaning segments actually tested, into multiple pieces. In any event, the two vendors do agree on this match, even though DNA.Land breaks the matching segment into two pieces where GedMatch and Family Tree DNA do not. I’m presuming (I hate that word) that this is the one segment that Ancestry calls as a match as well, because it’s the longest, but Ancestry’s Timber algorithm downgrades the match portion of that segment by removing 11cM (according to DNA.Land) from 29cM to 18cM or removes 13cM (according to both GedMatch and Family Tree DNA) from 31cM to 18cM. Both GedMatch and Family Tree DNA agree and appear to be accurate at 31cM.
  • Of the total 39 matching segments of any size, utilizing the 3cM threshold and 100 SNPs, which I set artificially very low, GedMatch only found 10 matching segments with any portion of the segment in common, meaning that at least 29 were entirely erroneous matches.
  • Resetting the GedMatch match threshold to 3 cM and 300 SNPS, a more reasonable SNP threshold for 3cM, GedMatch only reports 3 matching segments, one of which is chromosome 8 (undivided) which means at this threshold, 36 of the 39 matching DNA.Land segments are entirely erroneous. Setting the threshold to a more reasonable 5cM or 7cM and 500 SNPs would result in only the one match on chromosome 8.

  • If 29 of 39 segments (at 3cM 100 SNPs) are erroneously reported, that equates to 74.36% erroneous matches due to imputation alone, with out considering identical by chance (IBC) matches.
  • If 35 of 39 segments (at 3cM 300 SNPs) are erroneously reported, that equates to 89.74% percent erroneous matches, again without considering those that might be IBC.

Predicted vs Actual

One additional piece of information that I gathered during this process is the predicted relationship.

Vendor Total cM Total Segments Longest Segment Predicted Relationship
DNA.Land 162 to 3 cM 39 to 3 cM 17.3 & 12, split 3C
GedMatch 123 to 3 cM 27 to 3 cM 31.5 5.1 gen distant
Family Tree DNA 40 to 1 cM 12 to 1 cM 32 3-5C
MyHeritage No match No match No match No match
Ancestry 18.1 1 18.1 5-8C
23andMe 26 1 26 3-6C

Karen utilized her Ancestry file and I used my Family Tree DNA file for all of the above matching except at 23andMe and Ancestry where we are both tested on the vendors’ platform. Neither 23andMe nor Ancestry accept uploads. I included the 23andMe and Ancestry comparisons as additional reference points.

The lack of a match at MyHeritage, another company that implements imputation, is quite interesting. Karen and I, even with a significantly sized segment are not shown as a match at MyHeritage.

If imputation actually breaks some matching segments apart, like the chromosome 8 segment at DNA.Land, it’s possible that the resulting smaller individual segments simply didn’t exceed the MyHeritage matching threshold. It would appear that the MyHeritage matching threshold is probably 9cM, given that my smallest segment match of all my matches at MyHeritage is 9cM. Therefore, a 31 or 32 cM segment would have to be broken into 4 roughly equally sized pieces (32/4=8) for the match to Karen not to be detected because all segment pieces are under 9cM. MyHeritage has experienced unreliable matching since their rollout in mid 2016, so their issue may or may not be imputation related.

The Common Ancestor

At Family Tree DNA, Karen does not match my mother, so I can tell positively that she is related through my father’s line. She and I triangulate on our common segment with three other individuals who descend from Abraham Estes 1647-1720 .

Utilizing the chromosome browser, we do indeed match on chromosome 8 on a long segment, which is also our only match over 5cM at Family Tree DNA.

Based on our trees as well as the trees of our three triangulated Estes matches, Karen and I are most probably either 8th cousins, or 8th cousins once removed, assuming that is our only common line. I am 8th cousins with the other three triangulated matches on chromosome 8. Karen’s line has yet to be proven.

Imputation Matching Summary

I like the way that DNA.Land presents some of their features, but as for matching accuracy, you can view the match quality in various ways:

  1. DNA.Land did find the large match on chromosome 8. Of course, in terms of matching, that’s pretty difficult to miss at roughly 30cM, although MyHeritage managed. Imputation did split the large match into two, somehow, even though Karen and I match on that same segment as one segment at other vendors comparing the same files.
  2. Of the 39 DNA.Land total matches, other than the chromosome 8 match, two other matches are partial matches, according to GedMatch. Both are under 7cM.
  3. Of DNA.Land’s total 39 matches, 35 are entirely wrong, in addition to the two that are split, including two inaccurate imputed matches at over 5cM.
  4. At DNA.Land, I’m not so concerned about discerning between “real” and “false” small segment matches, as compared to both FTDNA and GedMatch, as I am about incorrectly imputed segments and matches. Whether small matches in general are false positives or legitimate can be debated, each smaller segment match based on its own merits. Truthfully, with larger segments to deal with, I tend to ignore smaller segments anyway, at least initially. However, imputation adds another layer of uncertainty on top of actual matching, especially, it appears, with smaller matches. Imputing entire segments of incorrect DNA concerns me.
  5. Having said that, I find it very concerning that MyHeritage who also utilizes imputation missed a significant match of over 30cM. I don’t know of a match of this size that has ever been proven to be a false match (through parental phasing), and in this case, we know which ancestor this segment descends from through independent verification utilizing multiple other matches. MyHeritage should have found that match, regardless of imputation, because that match is from portions of the two files that were both tested, not imputed.

Summary

To date, I’m not impressed with imputation matching relative to genetic genealogy at either DNA.Land or MyHeritage.

In one case, that of DNA.Land, imputation shows matches for segments that are not shown as matches at either Family Tree DNA or GedMatch who are comparing the same two testers’ files, but without imputation. Since DNA.Land did find the larger segment, and many of their smaller segments are simply wrong, I would suggest that perhaps they should only show larger segments. Of course, anyone who finds DNA.Land is probably an experienced genetic genealogist and probably already has files at both GedMatch and Family Tree DNA, so hopefully savvy enough to realize there are issues with DNA.Land’s matching.

In the second imputation case, that of MyHeritage, the match with Karen is missed entirely, although that may not be a function of imputation. It’s hard to determine.  MyHeritage is also comparing the same two files uploaded by Karen and I to the other vendors who found that match, both vendors who do and don’t utilize imputation.

Regardless of imputing additional locations, MyHeritage should have found the matching segment on chromosome 8 because that region does NOT need to be imputed. Their failure to do so may be a function of their matching routine and not of imputation itself. At this point, it’s impossible to discern the cause. We only know, based on matching at other vendors, that the non-match at MyHeritage is inaccurate.

Here’s what DNA.Land has to say about the imputed VCF file, which holds all of your imputed values, when you download the file. They pull no punches about imputation.

“Noisey and probabilistic.” Yes, I’d say they are right, and problematic as well, at least for genetic genealogists.

Extrapolating this even further, I find it more than a little frightening that my imputed data at DNA.Land will be utilized for medical research.

Quoting now from Promethease, a medical reference site that allows the consumer to upload their raw data files, providing consumers with a list of SNPs having either positive or negative research in academic literature:

DNA.land will take a person’s data as produced by such companies and impute additional variants based on population frequency statistics. To put this in concrete terms, a person uploading a typical 23andMe file of ~700,000 variants to DNA.land will get back an (imputed) file of ~39 million variants, all predicted to be present in the person. Promethease reports from such imputed files typically contain about 50% more information (i.e. 50% more genotypes) than the corresponding reports from raw (non-imputed) data.

Translated, this means that your imputed data provides twice as much “genetic information” as your actual tested data. The question remains, of course, how much of this imputed data is accurate.

That will be the topic of the third imputation article. Stay tuned.

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Concepts – Imputation

Until recently, the word imputation wasn’t a part of the vocabulary of genetic genealogy, but earlier this year, it became a factor and will become even more important in coming months.

Illumina, the company that provides chips to companies that test autosomal DNA for genetic genealogy has obsoleted their OmniExpress chip previously in use, forcing companies to utilize their new Global Screening Array (GSA) chip when their current chip supply runs out.

Only about 20% of the DNA locations previously tested by genetic genealogy companies are tested on this new platform. Illumina has encouraged vendors to utilize the process called imputation to infer DNA results for their customers that are common in populations, but has not been directly tested in customer’s DNA, in order for vendors to achieve backwards compatibility with people previously tested on the OmniExpress chip. You can read the technical details of imputation in a document produced by Illumina here.

LivingDNA, who was developing and launching a new product during the transition time between chips was the first vendor out the gate with a GSA product. Illumina represented imputation to be “very accurate” to LivingDNA, which is consequently how they represented the results to a group of genetic genealogists on a conference call in early 2017. LivingDNA was the lucky company to have the opportunity to “work the bugs out” with Illumina – said with tongue firmly in cheek. LivingDNA provides a list of papers describing their methods here.

Another company, MyHeritage also uses imputation, for an entirely different reason. My Heritage uses imputation to “add” to the DNA results of people who upload results from different vendors. They are the first company to attempt DNA matching between people using imputation, and they initially had and continue to have matching issues. In their initial release blog in September 2016, they state that imputation matching “is accomplished with very high accuracy.” In their Q&A blog in November 2016, they state that “imputation may introduce errors so we are in the process of fine-tuning it.” They have made changes since matching was originally introduced, but they still struggle with matching accuracy, most recently discussed by Leah Larkin in her article, MyHeritage Matching.

DNA.LAND does not perform testing, but is a nonprofit in the health care industry who  utilizes imputation for health-related research – imputing approximately 38.3 million locations in addition to the 700,000 locations in customers’ uploaded files. In order to encourage people to upload their test results, DNA.LAND performs matching and ethnicity reporting. Like MyHeritage, their matching results are problematic. DNA.LAND explains about imputation and summarizes by stating that “any reported value should never be taken as-is without further careful analysis.” I will be publishing an article shortly about DNA.LAND.

23andMe, on August 9, 2017, released their V5 product utilizing the new GSA chip. They have not said how they are addressing the imputation challenge and backward compatibility. Several issues have been reported.

As you can see, the genetic genealogy landscape is changing and like it or not, imputation is a part of the new scenery.

What, Exactly, is Imputation?

Imputation is the process whereby your DNA is tested and then the results “expanded” by inferring results for additional locations, meaning locations that haven’t been tested, by using information from results you do have. In other words, the DNA is adjacent locations is predicted, or imputed, by their association with their traveling companions.  In DNA, traveling companions are often known to travel together, but not always.

Imputation is built upon two premises:

1 – that DNA locations are usually inherited together in groups in a process known as linkage disequilibrium.

2 – that people from common populations share a significant amount of the same DNA

An example that DNA.LAND provides is the following sentence.

I saw a blue ca_ on your head.

There are several letters that are more likely that others to be found in the blank and some words would be more likely to be found in this sentence than others.

A less intuitive sentence might be:

I saw a blue ca_ yesterday.

DNA.LAND also says very clearly that imputed values can be incorrect. They also state that the values inferred are the common values, not rare mutations, and imputed results are most accurate in Caucasian populations and least accurate in African populations whose DNA is the most variant of any continental group. They caution against using these results for medical diagnosis.

SNPedia (Promethease) cautions against using imputed results as well and suggests that files utilizing only tested results, without imputed results, are more accurate.

Why Imputation?

Looking at this Autosomal SNP Comparison Chart, provided by the ISOGG Wiki, you can see the difference in the number of actual common locations tested by the various vendors.

This means that companies that allow uploads from different vendors utilizing widely divergent chip results have to do something in order to successfully compare the disparate files against each other for matching. Using  23andMe as an example, even though they don’t allow uploads from other companies, they have to do something to accommodate matching between the new GSA V5 chip and their earlier V3 and V4 chips.

Imputation Example

Let’s take a look at how imputation is used to “equalize” files uploaded from various vendors that only contain marginal amounts of overlap.

I’m using MyHeritage as an example. Imputation, in this case, is utilized in an attempt to make marginally compatible files more compatible.

The files from the Ancestry V2 kit and the Family Tree DNA kit have only about 382,000 locations in common, meaning about 300,000 locations are not in common. In order to attempt to equalize these and other kits, MyHeritage attempts to use imputation to deduce the DNA that a tester would/should/might have in the missing segments, based on various statistical factors that include the tester’s population and existing DNA.

Please note that for purposes of concept illustration, I have shown all of the common locations, in blue, as contiguous. The common locations are not contiguous, but are scattered across the entire range that each vendor tests.

You can see that the number of imputed locations for matching between two people, shown in tan, is larger than the number of actual matching locations shown in blue. The amount of actual common data being compared is roughly 382,000 of 1,100,000 total locations, or 35%.

Stay tuned for an upcoming series of articles about imputation and results in various scenarios.