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Autosomal DNA Transfers – Which Companies Accept Which Tests?

Roberta Estes

Somehow, I missed the announcement that Family Tree DNA now accepts uploads from MyHeritage.

Other people may have missed a few announcements too, or don’t understand the options, so I’ve created a quick and easy reference that shows which testing vendors’ files can be uploaded to which other vendors.

Why Transfer?

Just so that everyone is on the same page, if you test your autosomal DNA at one vendor, Vendor A, some other vendors allow you to download your raw data file from Vendor A and transfer your results to their company, Vendor B.  The transfer to Vendor B is either free or lower cost than testing from scratch.  One site, GedMatch, is not a testing vendor, but is a contribution/subscription comparison site.

Vendor B then processes your DNA file that you imported from Vendor A, and your results are then included in the database of Vendor B, which means that you can obtain your matches to other people in Vendor B’s data base who tested there originally and others who have also transferred.  You can also avail yourself of any other tools that Vendor B provides to their customers.  Tools vary widely between companies.  For example, Family Tree DNA, GedMatch and 23andMe provide chromosome browsers, while Ancestry does not.  All 3 major vendors (Family Tree DNA, Ancestry and 23andMe) have developed unique offerings (of varying quality) to help their customers understand the messages that their unique DNA carries.

Ok, Who Loves Whom?

The vendors in the left column are the vendors performing the autosomal DNA tests. The vendor row (plus GedMatch) across the top indicates who accepts upload transfers from whom, and which file versions. Please consider the notes below the chart.

(Chart updated September 28, 2017)

Please note that on August 9, 2017, 23and Me began processing on the Illumina GSA chip which is not compatible with earlier versions.  As of late September 2017, only GedMatch accepts their upload and only in their Genesis sandbox area, not the normal production matching area.  This is due to the small overlap area with existing chips.  You can read more about the GSA chip and its ramifications here

Incompatible Files

Please be aware that vendors that accept different versions of other vendors files can only work with the tested locations that are in the files generated by the testing vendors unless they use a technique called imputation.

For example, Family Tree DNA tests about 700,000 locations which are on the same chip as MyHeritage, 23andMe V3 and Ancestry V1. In the later 23andMe V4 test, the earlier 23andMe V2 and the Ancestry V2 tests, only a portion of the same locations are tested.  The 23andMe V4 and Ancestry V2 chips only test about half of the file locations of the vendors who utilize the Illumina OmniExpress chip, but not the same locations as each other since both the Ancestry V2 and 23andMe V4 chips are custom. 23andMe and Ancestry both changed their chips from the OmniExpress version and replaced genealogically relevant locations with medically relevant locations, creating a custom chip.

Update:  In August 2017, 23andMe introduced their V5 chip which has only about 20% overlap with previous chips.

I know this is confusing, so I’ve created the following chart for chip and test compatibility comparison.

(Chart updated Sept. 28, 2017)

You can easily see why the FTDNA, Ancestry V1, 23andMe V3 and MyHeritage tests are compatible with each other.  They all tested utilizing the same chip.  However, each vendor then applies their own unique matching and ethnicity algorithms to customer results, so your results will vary with each vendor, even when comparing ethnicity predictions or matching the same two individuals to each other.

Apples to Apples to Imputation

It’s difficult for vendors to compare apples to apples with non-compatible files.

I wrote about imputation in the article about MyHeritage, here and also more generally, here. In a nutshell, imputation is a technique used to infer the DNA for locations a vendor doesn’t test (or doesn’t receive in a transfer file from another vendor) based on the location’s neighboring DNA and DNA that is “normally” passed together as a packet.

However, the imputed regions of DNA are not your DNA, and therefore don’t carry your mutations, if any.

I created the following diagram when writing the MyHeritage article to explain the concept of imputation when comparing multiple vendors’ files showing locations tested, overlap and imputed regions. You can click to enlarge the graphic.

Family Tree DNA has chosen not to utilize imputation for transfer files and only compares the actual DNA locations tested and uploaded in vendor files, while MyHeritage has chosen to impute locations for incompatible files. Family Tree DNA produces fewer, but accurate matches for incompatible transfer files.  MyHeritage continues to have matching issues.

MyHeritage may be using imputation for all transfer files to equalize the files to a maximum location count for all vendor files. This is speculation on my part, but is speculation based on the differences in matches from known compatible file versions to known matches at the original vendor and then at MyHeritage.

I compared matches to the same person at MyHeritage, GedMatch, Ancestry and Family Tree DNA. It appears that imputed matches do not consistently compare reliably. I’m not convinced imputation can ever work reliably for genetic genealogy, because we need our own DNA and mutations. Regardless, imputation is in its infancy today and due to the Illumina GSA chip replacing the OmniExpress chip, imputation will be widely used within the industry shortly for backwards compatibility.

To date, two vendors are utilizing imputation. LivingDNA is using imputation with the GSA chip for ethnicity, and MyHeritage for DNA matching.

Summary

Your best results are going to be to test on the platform that the vendor offers, because the vendor’s match and ethnicity algorithms are optimized for their own file formats and DNA locations tested.

That means that if you are transferring an Ancestry V1 file, a 23andMe V3 file or a MyHeritage file, for example, to Family Tree DNA, your matches at Family Tree DNA will be the same as if you tested on the FTDNA platform.  You do not need to retest at Family Tree DNA.

However, if you are transferring an Ancestry V2 file or 23andMe V4 file, you will receive some matches, someplace between one quarter and half as compared to a test run on the vendor’s own chip. For people who can’t be tested again, that’s certainly better than nothing, and cross-chip matching generally picks up the strongest matches because they tend to match in multiple locations. For people who can retest, testing at Family Tree DNA would garner more matches and better ethnicity results for those with 23andMe V2 and V4 tests as well as Ancestry V2 tests.

For absolutely best results, swim in all of the major DNA testing pools, test as many relatives as possible, and test on the vendor’s Native chip to obtain the most matches.  After all, without sharing and matching, there is no genetic genealogy!

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Disclosure

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.

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