GEDMatch is an online suite of tools that help you analyze and compare your DNA and GEDCOM files to those of other people. This site can help you find matches regardless of which service did their DNA test. The tools also allow you to compare family trees and to connect DNA matches with their family trees.
Most of the core GM services are free. The site is supported by donations, and so some advanced tools are available only to donors who contribute to support the cost of running the site.
Everyone who has had their DNA tested for genealogical purposes should consider having their DNA data and GEDCOM added to GEDMatch. It is possible for one person to manage the kits for multiple people on GEDMatch, and it may be appropriate to allow the family genealogist (someone who is interested and adept with computers) to manage your information on GEDMatch. It is not necessary to create a separate GEDMatch account for each kit. One account can manage multiple DNA kits.
Why Would I Want to Do This?
There are several companies that do autosomal DNA (atDNA) testing. At the time of this writing, the major players are 23andMe, AncestryDNA (Ancestry), FamilyTreeDNA (FTDNA) and MyHeritageDNA (MyHeritage). There are others, and there will probably be more.
Here is the problem: Each company above will test your atDNA in a laboratory, then offer tools on their web site to match your results to other customers, on their site. If you tested on 23andMe you can compare your matches to everyone else in their database who is willing to share their DNA results. If you test on Ancestry, you will be matched against all the people who tested with Ancestry. To maximize matching your DNA to other people who have been tested, you would have to run the same atDNA test with all four companies. The laboratory results generated will be similar (not the same) for all four. So you would have to shell out between $70 and $100 to each company for mostly the same data, plus the opportunity to match against the other people who tested who are in their database. What is needed is a central clearing house where all atDNA kits can be compared. That is what GEDMatch does, among other things.
Another problem is specific to Ancestry. They provide you with a list of potential matches and relationships, but no DNA browsing visualization tools. The others provide tools that let you see which chromosomes and segments are matching, which is necessary to do any real genetic genealogy.
Some services, specifically FTDNA and MyHeritage, allow you to upload your raw data from other testing companie to compare against their database of tested individuals. This is worth doing, even if you become a GedMatch guru. Only a fraction of individuals who test on each service will upload their raw DNA data to GedMatch. So, to maximize the breadth of your search for relatives, make yourself findable in as many databases as you can.
GedMatch provides other DNA tools that can help you analyze your own DNA, and also compare your DNA to potential relatives.
How to Upload to GEDMatch
I have another page that includes instructions about how to download your DNA kit from each of the testing services. Use those instructions to download your DNA data to a ZIP file on your workstation.To be continued …