Save Even MORE at Family Tree DNA – Join a Project! (Plus This Week’s Coupons)

In addition to the first three money saving discounts on Y DNA tests from Family Tree DNA, there’s yet another way to save even MORE money:

  • Holiday Sale Prices on all products – listed here
  • Free 111 marker upgrade with Big Y – described here
  • Why the Big Y Test? – discussed here
  • Weekly coupons – listed on everyone’s personal page and I’ll be sharing mine weekly – see below
  • Join a project (for those who have not yet Y DNA tested)

Yes, you can save even more money by joining a project.

How does that work?

How Can I Save More By Joining A Project?

The free 111 marker upgrade with a Big Y test requires you to test or have tested at some level before you can order a Big Y test.

That means anyone who has tested even at the 12 marker level can purchase the Big Y and obtain the 111 upgrade for free.

Outside of a project, customers can only order a minimum of a 37 marker test – because that’s really the minimum informative test today. Typically a 12 marker test would only be useful to rule out a possible match.  But in this case, in order to purchase the Big Y for someone who has never tested before – the 12 marker test is suddenly VERY useful.

By joining a project, you can still purchase a 12 marker test and that reduces the Big Y bundle price yet again.

For people who have not done any Y DNA testing, this is an unbelievable value.

Joining A Project

To find an appropriate Y DNA project to join, go to the main Family Tree DNA page and type the surname of the man to be tested into the “Search your Surname” box.

I typed Estes.

You will then be shown various projects where the project administrators have listed Estes as one of the surname that is of interest to their project members.

I’m clicking on the Estes project, because Estes men should join the Estes project.  (You can join other projects later.)

You can see that the 12 marker Y DNA project is showing as an available purchase option for $59, above.

By clicking the orange “order now” button, you can order the 12 marker test for $59, further reducing the cost of testing.

You will automatically be joined to this project, and you can join other projects later.

It’s a Little More Complicated – But Not Much

Since the Big Y is only an upgrade test – meaning you must take any Y DNA STR test before ordering the Big Y – this means that your Y DNA test must be registered to your account before you can order the upgrade.

In Family Tree DNA lingo, this means that your order must be entered into a batch. Orders are batched at the end of the day every Monday and Wednesday, so if you will be able to upgrade to the Big Y as soon as your STR panel test, Y12 in this case, is batched.

Now, the challenge is of course that the Big Y coupons could be long gone by the time your order is batched.  You might need to order the Y12 this week, then wait until next week and hope you’re quick enough to find a Big Y coupon.

When you’re ready to upgrade, sign in to the account where you ordered the STR panel test and simply click upgrade, order the Big Y, and you’ll receive the 111 upgrade for free.

This strategy, even though it is slightly more complicated, will save you $$.

How much money, you ask?

Savings

The savings with this approach is even better. You can save a total of $424 as compared with purchasing these products individually.  And the projects will love having additional people join.  This benefits everyone, because projects are the best sources for help with your results.

There are at least some $50 Big Y discount coupons available as well as $25.

After your results are back, please be sure to join the appropriate haplogroup projects too. A haplogroup designation is part of what you receive when you test. The haplogroup project administrators are experts in their particular haplogroup – and what that means to you!

Additional Coupons

Every Monday Family Tree DNA issues Holiday Reward coupons between now and the end of the year.  If you (or someone) uses your coupon to purchase something, Family Tree DNA issues you a second Bonus Reward.

  1. First, I’d like to give a big shout out to my cousin, Jim, who contributed his coupons in addition to mine, below. You can see from the sheer number that we’re both seriously genetic genealogy addicted.
  2. Second, please do me a favor, and if you make a purchase, especially using one of the coupons, I’d really appreciate it if you use my affiliate link.  I receive a small commission if you use my link, and it doesn’t cost you a penny more. It helps keep the lights on for me (and keeps the blog free for everyone) – so if you enjoy and utilize this blog – please click through to purchase and don’t just gather the coupon numbers and post them elsewhere.
  3. Third, if you want to be among the first to receive these e-mails with coupons and other hot-off-the-presses information, subscribe by clicking on the little grey “follow” button on the upper right hand corner of the main blog page at www.dna-explained.com.

So, please click here to sign on and redeem the coupons below, purchase a product or upgrade! Thanks and enjoy the savings!

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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

Why the Big Y Test?

My recent article about the Big Y test sale and coupons bundled with a free 111 marker upgrade at Family Tree DNA generated quite a number of questions about the Big Y DNA test itself, and why a male might want to take one. I’ll answer that question, along with a few more that have arisen, as well sharing some of my coupons.

Why the Big Y?

Y DNA tests test a man’s direct paternal (usually surname) line and fall into two groups.

  • STRs – Short Tandem Repeats
  • SNPs – Single Nucleotide Polymorphisms

The first group, STRs, are the typical 12, 25, 37, 67 and 111 Y DNA tests.  STR marker location values change rapidly, as compared to SNPs which mutates more slowly.

Each STR test tests the number of STR markers it’s named for. In other words, a 37 marker test tests 37 marker locations with the goal of matching other men with the same surname. Often, as you test higher levels, the results become much more specific and you “lose” matches to men with non-matching surnames. In this case, “losing” is a good thing, like weight!

The closer the STR match on more markers, the more reliable the results. Fewer matches generally mean we’re filtering out the more distant matches in time and the closer in time you shared a common ancestor with the people you match the most closely on the highest marker test you’ve both taken.

In other words, you might match 50 people at 37 markers, but only 20 at 67 markers and 4 at 111 markers.  Those 4 men are the most closely related to you on that direct paternal line – which is why we strongly suggest that people upgrade to 111 markers.

You can see in this example from the Estes project that the first two people whose surname is Estes are not biologically descended from the same male as the last four individuals – because their STR markers showing in the project are quite different.

Because STR markers mutate more rapidly, they are very useful for genealogy – and are used for that purpose.  An exact high marker match (typically 37, 67 or 111) to a male with the same surname indicates that you share a common ancestor with that man, probably within the past few generations and certainly since the advent of surnames. STR mutations sometimes happen independently in different lines, and when that happens, it’s called matching by convergence.

SNPs, on the other hand, are much more stable and mutate at a much slower rate and are therefore sometimes not as useful for traditional genealogy – BUT – they have the power to look further back in time where we have no tools other than DNA to make discoveries about our ancestors.

In general, but not always, men known to descend from a common ancestor will share the exact same “terminal SNP” – meaning the SNP mutation that happened the most recently.  Sometimes a SNP mutation will have happened in the past few generations and men who share a common ancestor since the advent of surnames will have a different terminal SNP, but not often and if they do, it’s generally only one step down the haplotree from each other. Just the “son” leaf on that branch.

On the Big Y haplotree, above, of an Estes male, five people match him on the BY490 branch, six on the BY482 branch above, and so forth. Of course, the next question is who matches him on these branches, so he will look at his Big Y match list to see those individuals.

What this means is that, in general, SNPs define more distant clan relationships, because they happen less often, and STRs define more recent surname relationships – although the more SNPs that are discovered – the more instances of some overlap we see.

The following chart shows where the two kinds of testing are the most useful – which illustrates why we need both kinds of testing.

Sometimes, there are no new SNP mutations that have occurred in a particular since the adoption of surnames. Of course, there is an exception to every guideline, and it just might be you. In fact, it could be between you and your father, or your father and his father. You don’t know what you don’t know and the only avenue to discovery is DNA testing.

What Does the Big Y Do?

While the STR panel tests specific addresses on the Y DNA to read a specific location – the Big Y test is a scan that scans the majority of the Y chromosome.

In other words, the 37 marker test provides you with results for 37 individual locations, or alleles, on the Y chromosome by measuring the number of repeats found at those locations specifically.

However, the more DNA addresses to be checked, the more expensive the test – which is why STR testing is broken into panels.

The Big Y test scans the majority of the Y chromosome to compare to a standard Y DNA pattern.  Because scan technology, known as NGS or next generation sequencing, allows us to look at tens of thousands of locations, it is not as accurate as looking at one specific location (think google satellite view versus driving down the street).  The DNA sequencing equipment scans the entire Y chromosome several times, like 25 or 30, and then reports on how many times something out of the ordinary is seen at a specific location.

If the scan spots something unusual 10 times or more, it’s called as a positive “result.”  Ten times or less, it’s considered a blip and not a high enough confidence result to consider as a valid result to report to a customer.

Why Do You Care?

As a customer, you may not care about the scans and underlying scientific processes that I just described – but you do care about the outcome which is your confirmed haplogroup closest in time to you on the tree. That information is important genealogically.

The Y DNA haplotree is the result of mutations that occurred every few hundred or few thousand years over the lifetime of mankind.  The mutation that identifies you the most closely with your closest male relatives is the last mutation that occurred that you all share – or don’t – which means a new mutation happened since the advent of your surname, assuming you do actually descend from a common ancestor and don’t just circumstantially carry the same surname. Yes, that does occasionally happen.

The result for the customer who takes the Big Y test is that the haplogroup predicted through STR testing is confirmed and generally several more branches and leaves are added to your own personal haplogroup tree.

Family Tree DNA very accurately predicts your branch haplogroup when you take an STR test, but it’s a major branch, near the tree, not a small branch and certainly not a leaf.  Smaller branches can’t be accurately predicted nor larger branches confirmed without SNP testing. The most effective way to SNP test for already discovered haplogroups – plus new ones never before found – perhaps unique to your line – is to take the Big Y.

While all of this science may not sound exciting at first glance, the results certainly can be, for a genealogist anyway.

The Big Y:

  • Confirms estimated haplogroups.
  • Provides you with your haplogroup closest in time – meaning puts twigs and leaves on your branches.
  • Helps to build the Y DNA tree, meaning you can contribute to science while learning about your own ancestors.
  • Confirms that men who do match on the same STR markers really ARE in the same haplogroup.
  • Shows matches further back in time than STRs can show.
  • Maps the migration of the person’s Y line ancestors.

Together, STR and SNP tests provide us with the closest mutations meaning the most genealogically relevant as well as (generally) older and more distant mutations, giving us at least some information before the age of surnames. This means you will match men who adopted surnames about the same time your ancestors did.  If you are a McDonald, you might match men whose surname is Campbell, as an example. Or, you might match men with Scandinavian surnames.  All of these pieces of information add to the story of your ancestors before surnames and records – the point at which your paternal line is unquestionably lost to traditional genealogy. Big Y testing is a way to reach back behind that veil.

How else will you ever learn the history of your ancestor in that timeframe? And why wouldn’t you want to?

Summary

If you are interested in discovering any of this information, the Big Y is the most thorough avenue for the genealogist.  You can purchase some SNP markers individually, but that gets expensive very quickly, and you can’t learn about any new markers your DNA might hold if you purchase only SNP markers previously known to exist. Y DNA holds hundreds or even thousands of SNPs with mutations to report.

Additionally, many men’s DNA also holds never-before-discovered SNP mutations.  You can’t discover those any way other than a Big Y test.

Who Should Purchase the Big Y?

  • Males who want to discover their ancestor’s story before the advent of surnames.
  • Men who want to confirm and extend their haplogroup.
  • Men who want to be pioneers and discover new SNPs in their DNA – never previously found.
  • Males who want to participate in research and building the Y DNA tree.
  • Males who have previously taken some level of STR tests at Family Tree DNA.

The Big Y is only an upgrade test. You can only see the Big Y as a purchase option on your account as an upgrade.  Click on the blue Upgrade button located in your Y DNA section or at the top right of your personal page.

Questions

  • I want to discover my father’s paternal line, but I’m a female. What can I do?

Answer – Test your father or brother, or a male relative who carries your father’s surname and descends from the common male ancestor through the direct paternal line.  The article, Concepts – Who To Test For Your Father’s DNA will help you find a male to test for your father’s line.

  • I’m a male, but I haven’t taken any Y DNA test? How can I take the Big Y?

Answer – Easy.  Just order the Y37 test at Family Tree DNA first – then add the Big Y after the Y 37 has been recorded on your account.

  • Is Family Tree DNA using the Big Y scan data to provide the 111 marker upgrade?

Answer – No, according to the lab, they can only reliably extract 72 of the 111 markers from Big Y scan data, reliably, and they do not want to have unreliable STR marker results in the data base, so they will be running the 111 upgrades on the traditional testing platform, not extracting from Big Y scanned data.

  • Is there a sale or coupons?

Answer – In fact, there is a sale, coupons AND you currently receive a free upgrade to 111 markers with the purchase of a Big Y. For example, let’s say that you have already purchased the 37 marker test, or you order that now. You can redeem a coupon (assuming you can find one) in addition to the sale price.  You can then upgrade to the Big Y, which means you receive BOTH the 67 and 111 free.  You can ALSO apply a Big Y coupon to the purchase, if you can fine one, as well.

Here’s an example.

In essence, you receive the entire Y DNA testing package, which would normally cost $912 for $569 which saves you $343.

  • I don’t want to take the Big Y test, I just want to order a 111 marker test. Can I do that?

Answer – Yes, just order the 111 marker test. It’s on sale too and you can redeem a coupon, below, for more savings.

  • I’ve already taken the 111 marker test? Do I still get a discount on the Big Y?

Answer – You still receive the sale price for the Big Y of $475 as well as a discount coupon, assuming you can find one. (See below.)

  • When I click to order the Big Y, I don’t see a free upgrade to 111 markers. How to I order the free upgrade?

Answer – You don’t have to select the free upgrade to 111 markers.  Everyone automatically receives the upgrade when you order the Big Y.  If you already ordered since the sale began, you will receive this without doing anything. Do, however, watch your account to be sure you do receive the upgrade.

  • Can I use coupons plus receive the free 111 marker upgrade when I purchase the Big Y?

Answer – Yes, you receive the sale price, plus you can use each coupon one time.  In addition, if you purchase the Big Y, you receive the 111 upgrade automatically.

  • Where can I find a discount coupon?

Answer – Every customer receives one each week on your personal page.  I will also be sharing mine each week. I shared some yesterday, at this link, and there are more below.

Click here to sign on, redeem your coupons (or mine below) and order. Happy Black Friday early!!!

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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.

Best Big Y Deal EVER – Includes FREE 111 Upgrade at Family Tree DNA

Sorry for these really short blog posts – but I’ve just heard from Elliott Greenspan about the best deal EVER at Family Tree DNA, on the Big Y test that includes a FREE STR upgrade.  I don’t think this has been announced officially, so please feel free to forward the link to this article! This deal is so good, I wish I was a male!!!

During the holiday sale which started last weekend, any customer who purchases the Big Y will receive a free upgrade to Y 111 from any level STR test.  You MUST currently have a Y DNA test either ordered or completed in the system.

This means that if you don’t currently have a Y DNA test, and you’re a male (or have a male you want to test,) you can place a Y DNA test for any level and then go in and order a Big Y test, using any coupons. This deal is in ADDITION to any coupons you may have. You may have to wait a bit to order the Big Y until your regular Y DNA test order is registered in the system.

You’ll get a coupon discount on both orders (regular test and Big Y), and you’ll receive the Big Y AND a free upgrade to 111 that you automatically receive when purchasing a Big Y.

Here are a few coupons from my kits that you can use for a purchase discount.  Check your own kit for more.

Click here to sign in and take advantage of the following specials:

  • Holiday pricing for everyone
  • Coupons
  • Free 111 upgrade with Big Y

If you have coupon numbers to share with others, feel free to list in the comments!

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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.

Family Tree DNA 2017 Holiday Sale Begins

I’m still on the road, but wanted to get this to everyone as soon as possible. I’ll resume my normal publication schedule soon. In the meantime, great news for anyone wanting to purchase DNA kits for the holidays. As most of you know, Family Tree DNA has a holiday sale every year that begins about this time in November – and today is the day!

They’ve announced this year’s holiday sale prices below.

Additionally, if you are a current customer, check your account home page for a Holiday Reward, which is an additional discount on something.

The holiday reward coupon can be applied one time only in ADDITION to the sale price.

Click this here to sign on, check your holiday reward, and order a new kit or upgrade an existing one. This is a great time to purchase kits for those holiday visits.

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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.

Concepts – DNA Recombination and Crossovers

What is a crossover anyway, and why do I, as a genetic genealogist, care?

A crossover on a chromosome is where the chromosome is cut and the DNA from two different ancestors is spliced together during meiosis as the DNA of the offspring is created when half of the DNA of the two parents combines.

Identifying crossover locations, and who the DNA that we received came from is the first step in identifying the ancestor further back in our tree that contributed that segment of DNA to us.

Crossovers are easier to see than conceptualize.

Viewing Crossovers

The crossover is the location on each chromosome where the orange and black DNA butt up against each other – like a splice or seam.

In this example, utilizing the Family Tree DNA chromosome browser, the DNA of a grandchild is compared to the DNA of a grandparent. The grandchild received exactly 50 percent of her father’s DNA, but only the average of 25% of the DNA of each of her 4 grandparents. Comparing this child’s DNA to one grandmother shows that she inherited about half of this grandmother’s DNA – the other half belonging to the spousal grandfather.

  • The orange segments above show the locations where the grandchild matches the grandmother.
  • The black sections (with the exception of the very tips of the chromosomes) show locations where the grandchild does not match the grandmother, so by definition, the grandchild must match the grandfather in those black locations (except chromosome tips).
  • The crossover location is the dividing line between the orange and black. Please note that the ends of chromosomes are notoriously difficult and inconsistent, so I tend to ignore what appear to be crossovers at the tips of chromosomes unless I can prove one way or the other. Of the 22 chromosomes, 16 have at least one black tip. In some cases, like chromosome 16, you can’t tell since the entire chromosome is black.
  • Ignore the grey areas – those regions are untested because they are SNP poor.

We know that the grandchild has her grandmother’s entire X chromosome, because the parent is a male who only inherited an X chromosome from his mother, so that’s all he had to give his daughter. The tips of the X chromosome are black, showing that the area is not matching the mother, so that region is unstable and not reported.

It’s also interesting to note that in 6 cases, other than the X chromosome, the entire chromosome is passed intact from grandparent to grandchild; chromosomes 4, 11, 16, 20, 21 and 22.

Twenty-six crossovers occurred between mother and son, at 5cM.  This was determined by comparing the DNA of mother to son in order to ascertain the actual beginning and end of the chromosome matching region, which tells me whether the black tips are or are not crossovers by comparing the grandchild’s DNA to the grandmother.

For more about this, you might want to read Concepts – Segment Survival – Three and Four Generation Phasing.

Before going on, let’s look at what a match between a parent and child looks like, and why.

Parent/Child Match

If you’re wondering why I showed a match between a grandchild and a grandparent, above, instead of showing a match between a child and a parent, the chromosome browser below provides the answer.

It’s a solid orange mass for each chromosome indicating that the child matches the parent at every location.

How can this be if the child only inherits half of the parent’s DNA?

Remember – the parent has two chromosomes that mix to give the child one chromosome.  When comparing the child to the parent, the child’s single chromosome inherited from the parent matches one of the parent’s two chromosomes at every address location – so it shows as a complete match to the parent even though the child is only matching one of the parent’s two of chromosome locations.  This isn’t a bug and it’s just how chromosome browsers work. In other words, the “other ” chromosome that your parents carry is the one you don’t match.

The diagram below shows the mother’s two copies of chromosome 1 she inherited from her father and mother and which section she gave to her child.

You can see that the mother’s father’s chromosome is blue in this illustration, and the mother’s mother’s chromosome is pink.  The crossover points in the child are between part B and C, and between part C and D.  You can clearly see that the child, when compared to the mother, does in fact match the mother in all locations, or parts, 3 blue and 1 pink, even though the source of the matching DNA is from two different parents.

This example shows the child compared to both parents, so you can see that the child does in fact match both parents on every single location.

This is exactly why two different matches may match us on the same location, but may not match each other because they are from different sides of our family – one from Mom’s side and one from Dad’s.

You can read more about this in the article, One Chromosome, Two Sides, No Zipper – ICW and the Matrix.

The only way to tell which “sides” or pieces of the parent’s DNA that the child inherited is to compare to other people who descend from the same line as one of the parents.  In essence, you can compare the child to the grandparents to identify the locations that the child received from each of the 4 grandparents – and by genetic subtraction, which segments were NOT inherited from each grandparent as well, if one grandparent happens to be missing.

In our Parental Chromosome pink and blue diagram illustration above, the child did NOT inherit the pink parts A, B and D, and did not inherit the blue part C – but did inherit something from the parent at every single location. They also didn’t inherit an equal amount of their grandparents pink and blue DNA. If they inherited the pink part, then they didn’t inherit the blue part, and vice versa for that particular location.

The parent to child chromosome browser view also shows us that the very tip ends of the chromosomes are not included in the matching reports – because we know that the child MUST match the parent on one of their two chromosomes, end to end. The download or chart view provides us with the exact locations.

This brings us to the question of whether crossovers occur equally between males and female children.  We already know that the X chromosome has a distinctive inheritance pattern – meaning that males only inherit an X from their mothers.  A father and son will NEVER match on the X chromosome.  You can read more about X chromosome inheritance patterns in the article, X Marks the Spot.

Crossovers Differ Between Males and Females

In the paper Genetic Analysis of Variation in Human Meiotic Recombination by Chowdhury, et al, we learn that males and females experience a different average number of crossovers.

The authors say the following:

The number of recombination events per meiosis varies extensively among individuals. This recombination phenotype differs between female and male, and also among individuals of each gender.

Notably, we found different sequence variants associated with female and male recombination phenotypes, suggesting that they are regulated by different genes.

Meiotic recombination is essential for the formation of human gametes and is a key process that generates genetic diversity. Given its importance, we would expect the number and location of exchanges to be tightly regulated. However, studies show significant gender and inter-individual variation in genome-wide recombination rates. The genetic basis for this variation is poorly understood.

The Chowdhury paper provides the following graphs. These graphs show the average number of recombinations, or crossovers, per meiosis for each of two different studies, the AGRE and the FHS study, discussed in the paper.

The bottom line of this paper, for genetic genealogists, is that males average about 27 crossovers per child and females average about 42, with the AGRE study families reporting 41.1 and the FHS study families reporting 42.8.

I have been collaborating with statistician, Philip Gammon, and he points out the following:

Male, 22 chromosomes plus the average of 27 crossovers = an average of 49 segments of his parent’s DNA that he will pass on to his children. Roughly half will be from each of his parents. Not exactly half. If there are an odd number of crossovers on a chromosome it will contain an even number of segments and half will be from each parent. But if there are an even number of crossovers (0, 2, 4, 6 etc.) there will be an odd number of segments on the chromosome, one more from one parent than the other.

The average size of segments will be approximately:

  • Males, 22 + 27 = 49 segments at an average size of 3400 / 49 = 69 cM
  • Females, 22 + 42 = 64 segments at an average size of 3400 / 64 = 53 cM

This means that cumulatively, over time, in a line of entirely females, versus a line of entirely males, you’re going to see bigger chunks of DNA preserved (and lost) in males versus females, because the DNA divides fewer times. Bigger chunks of DNA mean better matching more generations back in time. When males do have a match, it would be likely to be on a larger segment.

The article, First Cousin Match Simulations speaks to this as well.

Practically Speaking

What does this mean, practically speaking, to genetic genealogists?

Few lines actually descend from all males or all females. Most of our connections to distant ancestors are through mixtures of male and female ancestors, so this variation in crossover rates really doesn’t affect us much – at least not on the average.

It’s difficult to discern why we match some cousins and we don’t match others. In some cases, rather than random recombination being a factor, the actual crossover rate may be at play. However, since we only know who we do match, and not who tested and we don’t match, it’s difficult to even speculate as to how recombination affected or affects our matches. And truthfully, for the application of genetic genealogy, we really don’t care – we (generally) only care who we do match – unless we don’t match anyone (or a second cousin or closer) in a particular line, especially a relatively close line – and that’s a horse of an entirely different color.

To me, the burning question to be answered, which still has not been unraveled, is why a difference in recombination rates exists between males and females. What processes are in play here that we don’t understand? What else might this not-yet-understood phenomenon affect?

Until we figure those things out, I note whether or not my match occurred through primarily men or women, and simply add that information into the other data that I use to determine match quality and possible distance.  In other words, information that informs me as to how close and reasonable a match is likely to be includes the following information:

  • Total amount of shared DNA
  • Largest segment size
  • Number of matching segments
  • Number of SNPs in matching segment
  • Shared matches
  • X chromosome
  • mtDNA or Y DNA match
  • Trees – presence, absence, accuracy, depth and completeness
  • Primarily male or female individuals in path to common ancestor
  • Who else they match, particularly known close relatives
  • Does triangulation occur

It would be very interesting to see how the instances of matches to a certain specific cousin level – say 3rd cousins (for example), fare differently in terms of the average amount of shared DNA, the largest segment size and the number of segments in people descended from entirely female and entirely male lines. Blaine Bettinger, are you listening? This would be a wonderful study for the Shared cM Project which measures actual data.

Isn’t the science of genetics absolutely fascinating???!!!

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Helix Sale

Helix is a startup company (funded in part by the DNA testing juggernaut, Illumina) that is offering a marketplace approach to DNA testing.

This means you pay for the initial Exome sequencing through Helix, then you pay for apps from companies that develop applications, much like the app stores.

I will be reporting on my Neanderthal and Metabolism results soon, but Helix has launched a 2 day sale (ending November 9th) that is the best Exome pricing I’ve ever seen anyplace – and If you are interested, I don’t want you to miss the opportunity.

However, and this is a big however, you do NOT receive your raw data results, so you can’t download and use those results for genealogy or health outside of applications available for purchase through Helix affiliates.

If you are interested in testing for other types of information offered through Helix affiliate company applications, you may be interested in this sale.

Here’s how the Helix marketplace works:

You purchase an application and bundled into that price is both the Helix exome sequencing and the app itself.

On the Helix site, click on the various icons under the “shop” tab to see the regular and sale pricing.

At this point, the only three tests that I have confidence in are the Neanderthal and Metabolism apps by Insitome (a startup by Spencer Wells, former Director of the Genographic Project and Scientist in Residence), the Genographic Project app, and potentially the Health category apps, although I have not personally evaluated the Health apps.

In other cases, I’m downright skeptical of the value of some of these apps, but I’ll let you be the judge.

App categories, other than the ones I mentioned above, include:

  • Entertainment
  • Family
  • Fitness
  • Nutrition

Here’s are the sale prices for:

Disclosure

While I am a National Geographic Genographic affiliate researcher, there is no financial remuneration involved, nor is this a paid affiliate link.  This means I have no financial interest whatsoever, in any way, in these products and services – nor do I receive any commission if you purchase any of these products.