There are two or three types of data that testers may be able to download from DNA testing sites. Genealogy customers need to periodically download as much as possible.
- Raw data files needed for transferring DNA files from the company where you tested to other testing or analysis/comparison sites such as FamilyTreeDNA, MyHeritage, and GEDmatch for matching and other tools.
- Matching segment files which detail your matches, segment by segment with people whom you match.
- Match information files that provide you with additional information about your matches. What’s included varies by vendor.
This type of information is not uniformly available from all vendors, but is available as follows:
|Vendor||Raw Data File||Matching Segment File||Match Information File|
|GedMatch||Not a testing company, so no||Yes||Yes|
I have provided step-by-step information about how to download your raw DNA data files and upload them to other vendors in a series of articles that you can find here.
Some of the answers in the table above need caveats because each vendor is different. Let’s take a look.
Matching Segment Files
In this article, I’ll provide information about how to download your matching segment and match information file(s).
Unfortunately, Ancestry does not provide any segment data at all, nor do they provide a way to download your match information. Third-party tools that did this for you have been banned by Ancestry, under threat of legal action, so this information is no longer available to Ancestry customers.
You can’t obtain this information from Ancestry, but you can transfer your DNA file to other vendors such as FamilyTreeDNA, MyHeritage and the third-party site, GEDmatch where you’ll receive additional matches. Some Ancestry matches will have transferred elsewhere as well, and you can take advantage of your matching segment information.
Why Do I Want a Matching Segment File?
The matching segment file provides you with information about exactly how and where you match each person.
Here’s an example that includes the match name, chromosome, start and end location of the match along with the total number of CentiMorgans (cM) and total SNPs in the matching segment. Your matching segment file consists of hundreds/thousands of rows of this information.
Determining who matches you on the same segment is important because it facilitates the identification of common ancestors. Segment matching is also the first step in triangulation which allows you to confirm descent from common ancestors with your matches.
I wrote about triangulation at each vendor in the following articles:
- Triangulation in Action at Family Tree DNA
- Triangulation in Action at MyHeritage
- Triangulation in Action at 23andMe
- Triangulation in Action at GEDmatch
- Triangulation in Action at DNAPainter
Matching and Triangulation help you sort out legitimate matches, and which ancestors that DNA segment comes from.
Sorting For Legitimate Matches
On each segment location of your DNA, you will match:
- People from your Mom’s side
- People from your Dad’s side
- People that are identical by chance (IBC) where they match you because part of the DNA from your Mom’s side and part from your Dad’s side just happens to look like their DNA (or vice versa.)
You can see how matching works in this example of 10 DNA locations. You inherited half of your Mom’s DNA and half of your Dad’s.
- Legitimate maternal matches to you on this segment will have all As in this location.
- Legitimate paternal matches to you will have all Cs in this location.
- Identical by chance matches will match you, because they have the same DNA as both of your parents that you carry – interspersed. They will not match either of your parents individually.
IBC matches DO technically match you, but accidentally. In other words, they are identical by chance (IBC) because they just happen to match the DNA of both of your parents intermixed. Conversely, you can match the DNA of their parents intermixed as well. Regardless of why, they are not a legitimate maternal or paternal match to you.
For example, you can see that the identical by chance (IBC) match to you, above, won’t match the legitimate maternal or legitimate paternal matches.
When comparing your matches on any segment, you’ll wind up with a group of people who match you and each other on your maternal side, a group on your paternal side, and “everyone else” who is IBC.
I wrote about IBD, identical by descent DNA and IBC, identical by chance DNA and how that works, here.
A downloadable segment match file allows you to sort all of your matches by chromosome and segment. That’s the first step in determining if your matches match each other – which is how to determine if people are legitimate matches or IBC.
Match Information File
There’s a second file you’ll want to download as well except at 23andMe who includes all of the information in one file. You’ll want to download these files from each vendor at the same time so they are coordinated and include the same matches from the same time.
Downloading the second file, your match information, provides additional information which will be helpful for your genealogy. The information in this file varies by vendor, but includes items such as, but not limited to:
- Tree link
- Match date
- Predicted Relationship Range
- Actual Relationship
- Total shared cM
- Longest segment cM
- Maternal or paternal bucket (FamilyTreeDNA)
- Family Surnames
- Percent of shared DNA
You never know when vendors are going to change something that will affect your matches, like 23andMe did last fall, so it’s a good idea to download periodically.
Downloading your segment match and match information files are free, so let’s do this.
Downloading Your Segment Match & Information Files
Sign on to your account.
Under your Family Finder Autosomal DNA test results, click on Chromosome Browser.
On the chromosome browser page, at the top right, click on Download All Segments.
Caveat – if you access the chromosome browser through the Family Finder match page, shown below, you will receive the segment matches ONLY for the people you have selected.
After selecting specific matches, as shown above, the option on the chromosome browser page will only say “Download Segments.” It does NOT say “Download All Segments.”
Clicking on this link only downloads the segments that you match with those people, so always be sure to access “Download ALL Segments” directly through the chromosome browser selection on your Autosomal DNA Family Finder menu without going to your match page and selecting specific matches.
The segment download file includes only the segments, but not additional information, such as which side, maternal or paternal, those matches are bucketed to, surnames and so forth. You need to download a second file.
To download additional information about your matches, scroll to the very bottom of your Family Finder match page and click on either Download Matches or Download Filtered matches. If you’ve used a filter such as maternal or paternal, you’ll receive only those matches, so be sure no filters are in use to download all of your matches’ information.
Your reports will be downloaded to your computer, so save them someplace where you can find them.
Sign in to your account and click on the DNA tab, then DNA Matches.
At the far right-hand side, you’ll see three little dots. Click on the dots and you’ll see the options to export both the entire DNA Matches list and the shared DNA segment info for all DNA Matches.
You’ll want to download both. The first file Is the DNA matches list.
To download your segment matches, select the second option, “Export shared DNA segment info…”
Your files will be emailed to you.
At 23andMe, sign on to your account and click on “DNA Relatives” under the Ancestry tab.
You’ll see your list of matches. Scroll to the very bottom where you’ll see the link to “Download aggregate data.”
23andMe combines your segment and match information in one file.
Remember that at 23andMe, your matches are limited to 2000 (unless you’re a V5 subscriber), minus the number of people who have not opted in to Relative Sharing. Additionally, there will be a number of people in the download file whose names appear, but who don’t have any segment data. Those people opted-in to Relative Sharing, but not to share segment information.
For example, my download file has 2827 rows. Of those, 1769 are unique individuals, meaning that I have matches with multiple segments for 1058 people. This means that of my 2000 allowed matches, 231 (or more) did not opt-in for Relative Sharing. The “or more” means that 23andMe does not roll matches off the list if you have communicated with the person, so some people may actually have more than 2000 matches. It’s impossible to know how 23andMe approaches calculations in this case.
Of those 1769 unique individuals on my match list, 257, or 15% did not share segment information. I’d sure like for those to be automatically rolled off and replaced with the next 257 who do share. 1512 or roughly three-quarters, 75%, of my 2000 allowed matches are useful for genealogy.
Initially, when 23andMe made their changes last fall, they were reportedly limiting the download file number to 1000, but they have reversed that policy on the V3 and V4 chips. I downloaded files from both chip versions to confirm that’s true.
I don’t have the V5 chip subscription level, nor am I going to retest to do that, so I don’t know if V5 subscribers receive all 5000 of the allowed matches in their download file.
This is the perfect example of why it’s a good idea to download your match files periodically. 23andMe is the only testing vendor that restricts your matches and when they roll off your list, they are irretrievable.
Aside from that, safe is better than sorry. You never know when something will change at a vendor and you’ll wish you had downloaded your match files earlier.
GedMatch, a third-party vendor, provides lots of tools but isn’t intuitive and provides almost no tutorial or information about how to navigate or use their site. There are some YouTube videos and Kitty Cooper has written several how-to articles. GEDmatch has promised a facelift soon.
GEDmatch provides many tools for free, along with a Tier1 level which provides advanced features by subscription.
At GEDmatch, you can see up to 2000 matches for free, but you must be a Tier 1 subscription member to download your matches – and the download is restricted to your top 1000 matches.
There are two Tier 1 one-to-many comparison options that are very similar. For either, you’ll enter your kit number and make your selection. Given that you’re restricted to 1000 in the download, there is no reason to search for more than 1000 kits.
Then, click on Visualization options
You will then see the list of visualization options which includes “List/CSV.”
Clicking on “List/CSV” provides you with options.
You’ll want to select the Matched Segment List, and you can either select “Prevent Hard Breaks,” or not. Allowing hard breaks means that small non-matching regions between two matching segments is not ignored, and the two segments are reported as two separate segments – if they are large enough to be reported.
If you prevent hard breaks, non-matching regions of less than 500,000 thousand base positions are ignored, creating one larger blended segment. It’s my preference to allow hard breaks because I’ve seen too many instances of erroneously “blended” segments.
When your matching segment file is complete, you will be prompted to download to your computer.
Thanks to Genetic Affairs, I discovered an alternate way to obtain more than 1000 downloaded matches from GEDmatch.
GEDmatch Alternative Methodology
Genetic Affairs suggests using the DNA Segment Search with a minimum of 5000 kits, and to enable the option to “Prevent Hard Breaks.”
Do not close the session while GedMatch is processing or you’ll need to restart your query.
When finished click “Here” to download the file to your system.
Now you’re ready for part 2.
Next, you’ll want to select the Triangulation feature.
These functions take time, so you’ll be watching as the counter increases. Or maybe go eat dinner or research some genealogy.
I can hear the “Jeopardy countdown music…
When finished, click on “Here” to download this second file.
Whew! Now you should have your segment and match information files from each company that supports this information and provides downloads.
I generally save my files by vendor and date. However, if you’re going to use the files for a special project – you may want to make a copy elsewhere. For example, I’m going to use these files for Genetic Affairs’ AutoSegment feature, so I’ve downloaded fresh files from each vendor on the same date and made a separate copy, stored in my Genetic Affairs folder. I’ll let you know how that goes😊
- Test at vendors that don’t accept transfers. Ancestry and 23andMe
- Test at or transfer to the rest. FamilyTreeDNA, MyHeritage and GEDmatch
- Unlock or subscribe to the advanced tools that include chromosome browsers, ethnicity, and more, depending on the vendor. FamilyTreeDNA, MyHeritage, GEDmatch
- Upload or create trees at each vendor (except 23andMe who doesn’t support trees.)
- Download as much information as you can from each vendor.
- Work your matches through shared (in common with) matches, trees, segments, and clusters!
I receive a small contribution when you click on some of the links to 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.
DNA Purchases and Free Transfers
- FamilyTreeDNA – Y, mitochondrial and autosomal DNA testing
- MyHeritage DNA –Autosomal DNA test
- MyHeritage FREE DNA file upload – Transfer your results from other vendors free
- AncestryDNA – Autosomal DNA test
- 23andMe Ancestry – Autosomal DNA only, no Health
- 23andMe Ancestry Plus Health
Genealogy Products and Services
- MyHeritage FREE Tree Builder – Genealogy software for your computer
- MyHeritage Subscription with Free Trial
- Legacy Family Tree Webinars – Genealogy and DNA classes, subscription-based, some free
- Legacy Family Tree Software – Genealogy software for your computer
- Charting Companion – Charts and Reports to use with your genealogy software or FamilySearch
- RootsMagic Software – Genealogy software for your computer
- Genealogical.com – Lots of wonderful genealogy research books
- Legacy Tree Genealogists – Professional genealogy research