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Genomics is the Genomelink team’s passion and we have tried literally all kinds of DNA tests and websites out there. In this article, we’re introducing GEDmatch — one of the most popular tools to track down family members and family history using raw DNA data that you can get from DNA results like 23andMe or AncestryDNA.
What is GEDmatch?
GEDmatch.com is a great family finder tool for people who are interested in finding your relatives for FREE. It is commonly used by professional genetic genealogists for genealogy research. The core features include:
- One-To-Many DNA Comparison Result: Helps you compare your genetic profile from GEDmatch database. Their emails are provided so you can quickly contact them if you get a hit.
- One-to-One Autosomal DNA Comparison: This helps you narrow down the comparison with one specific relative member. Use this to confirm how much DNA data you actually share with that person before you reach out.
- Admixture (heritage): This is a well-known analysis for identifying your ethnic roots. Like AncestryDNA and 23andMe, it shows the proportion of your DNA coming from a particular ethnicity/geography. It’s interesting to compare these results with that of other ancestry tests.
There are numerous tools listed on the GEDmatch homepage that you can use for different purposes (as pictured below). For first-timers, we recommend starting out with the 3 tools listed above (boxed in red in the image below).
How to use GEDmatch?
First, upload your DNA data from DNA testing companies like AncestryDNA. After receiving the test results of your common ancestor, these companies allow you to download your own raw DNA data and upload that elsewhere to access different information, like GEDmatch.
List of companies whose raw data are compatible with GEDmatch (links to respective pages explaining how to download raw DNA data):
Once you’ve downloaded your raw data file, create a GEDmatch account and upload your data. (We’re writing a step-by-step guide on how to do this in another blog post). Note that it will take a few hours after uploading to see your results. They don’t notify you when it’s ready — but you can check the “Kit ID”, and if it says no kit number registered yet, you need to wait a little longer.
How to understand the results?
Once your results are ready, you are able to explore a number of features on GEDmatch. Here are two main tools:
1. One-To-Many DNA Comparison Result
When you click “One-To-Many DNA Comparison Result”, you can see a list of contacts like below.
How do you evaluate the results to determine who is a potential relative? Check “Overlap and Total cM” first.
Total cM” is the total length of all substantial DNA segments you share with a DNA match. “Overlap” is the total number of overlapping SNPs that you share with your match. SNPs are “single nucleotide polymorphisms.” You can think of them simply as DNA letters important in determining your unique genetic profile.
The table* below summarizes the total cM expected from different degrees of relations within the family. For example, if your parents’ data is on Gedmatch, they should show up as a match with over 3000 cM shared. If you do it with great-grandparents, it would be around 464-1486cM. Or 46-515cm with 2nd cousin.
*If you want further details, dnapainter’s comprehensive chart of cM calculator does a good job of explaining this. Note that DNA data files and their coverage of the genome differ across companies, so results may inevitably not be 100% accurate.
In conclusion, by checking “Overlap” and “Total cM”, you may find people who share significant amount of DNA with you — people who potentially are your newfound relatives!
2. One-to-One Autosomal DNA Comparison
Once you find someone who shares a good chunk of DNA data with you, you can start digging into the details of your DNA relationship with them. The image below is from the One-To-One DNA Comparison Result: it gives you a visual representation of which segments of your DNA you share with that person (chromosome browser). What you want to see is how many blue chunks do you have.
What else can we do with GEDmatch?
One-To-Many DNA Comparison Result and One-To-One DNA Comparison Result are awesome tools to start with. Besides those, here’s our recommendation for what else to try.
Try out Admixture / Oracle with Population Search. This helps you learn what genetic ethnicity you have based on publicly available genealogy databases such as MDLP, Eurogenes, Dodecad, etc. Here is a summary of the recommended databases to use based on your ethnicity.
MDLP — European
Eurogenes — European
Dodecad — Eurasians, Asians, Africans
HarappaWorld — South Asian
Ethiohelix — African
puntDNAL — (Unknown)
GedrosiaDNA — Eurasian (Indian and Asian)
Also, One to One X DNA Comparison is a unique feature that enables you to do the same comparison as "One-To-One DNA Comparison" for your X Chromosome. The main One to One comparison tool analyzes autosomal DNA, which is your numbered chromosomes commonly used by ancestry DNA companies. Y-DNA can trace your paternal line (father's side), X DNA does the same for your mother's side maternal line. You can learn more about how to use this tool on this post as well! ("How to Understand Gedmatch X One-to-One Results")
Was this helpful? If you have any additional questions about GEDmatch, feel free to leave a comment below or reach out to us at firstname.lastname@example.org. We’d love to hear about your experiences with DNA tests and websites!
This article was written by Genomelink team. Our mission is to help people learn and do more with their DNA data. Genomelink is a DNA data analysis platform where you can discover stuff about yourself from your DNA besides ancestry. Or 100+ genetic traits includes food & nutrition, personality, intelligence, fitness, and physical traits. Your first 25 traits are free. Join now!