Many of us ask Matches to upload to GEDmatch. Some do. Most are bewildered by what they see – I sure was, when I started! It’s particularly daunting with AncestryDNA Matches who generally don’t have any prior experience with DNA segments. Well, just a little noodling around can go a long way. This blog post will suggest some easy steps for anyone who has just uploaded to GEDmatch.
First the login. Your GEDmatch page is anchored on the email you used to sign up and a password you provided. If you forget your password, just enter your email and click on forgot password.
When your GEDmatch home page opens up – stop for a moment and look around.
– Messages from the GEDmatch Admin are at the top.
– Look at each of the big boxes:
– Information – your profile info.
– File Uploads – links to upload raw DNA data files on the left and links to upload a GEDCOM (Tree info) on the right (it pays to do both).
– Learn More – Several links to learn more about GEDmatch – not just yet, but soon, click on each link and look it over.
– Analyze Your Data – Just read the title of each of the Utilities for now; I’ll come back to some of them later.
– Your DNA Resources – a list of your GEDmatch kits (you can upload more kits). Note the EDIT or DELETE link.
– Your GEDCOM Resources – the GEDCOMs (Trees) you’ve uploaded.
– Tier 1 Utilities – some advanced utilities for user who pay a subscription (see bottom of your home page); see how much you’ll use GEDmatch before subscribing.
JUMP IN – Get your feet wet – take a utility on a trial run and see what it’s like! Start with the ‘One-to-one’compare – just click on that line. Enter your GEDmatch kit number in the first box; and someone else’s kit number in box 2. Usually someone has asked you to upload, and they should have given you their kit number. Then hit enter, or click on the Submit button. You’ll get a table of the DNA shared segment(s) with Chromosome, Start and End Locations, cM, SNP – this is the physical information about the DNA you share with a Match – see my blogpost here for more info. Under the chart are some other data, including “Estimated number of generations to MRCA” – please take this number with a grain of salt! It’s a calculated number. 1.0 means parent/child. As the number gets larger, it’s actually more of an average than anything specific. Don’t put a lot of stock into anything over 4.
Now – use your browser back arrow to get back to the Comparison Entry Form – it should have the two kit numbers still there. Select the button for Graphics and Positions to get a colorful display of your 22 chromosomes compared to your Match. Read the legend at the top with particular attention to the red (no match) and yellow (half match) – when the yellow (and green) is long enough, the utility will show a shared segment with a blue bar. And you’ll see the same table info you saw before. This view helps put the whole DNA matching thing in perspective. For most of your cousin Matches, the colorful chromosome bars will be alternating red and yellow (maybe a little green). This indicates that we match on a lot of our DNA, but just not in long stretches. Generally, you and a cousin Match will have only one stretch of matching yellow (and green) that is long enough to call a Match. As you read through this blog, you’ll learn that when the shared segments of different Matches overlap and match each other, you have a Triangulated Group, which can be very helpful.
NEXT STEP – Now that you’d tried the basic one-to-one compare, you’re ready to try the ‘One-to-many’ matches. Go back to your home page and click on that utility. Now just enter your GEDmatch kit number and click on Display Results. Please read the explanatory material at the top – all of it is important. Then scroll down to see your closest 2,000 Matches, arranged by closeness. For each one you’ll see the Kit Number; Autosomal and X-DNA data; each Match’s name/alias, and their email. Maybe you’ll recognize some of the top Matches from your testing company… Now click on the hyperlinked A in the Autosomal/Details column – you’ll see the one-to-one comparison page come up with your two kit numbers already filled in – just click on Submit to “see” the shared segment(s), as described above.
Put on your genealogist hat and email any of your Matches and share Trees and info to discover how you are related. To fully use the DNA data, read my blogposts about Triangulation. It takes a while to get up to speed on the DNA analysis, so I highly recommend using your genealogy hat for a while and get to know your cousins….
If you are trying to relate cM values to cousinship, there is a wide range of possibilities. Check out the August 2017 chart at ISOGG here.
ADMIXTURE – Try a test run. On your home page, click on “Admixture (heritage)”. Select, say, Eurogenes, and click on Continue. Enter your kit number in the box; and click on Continue. Look over your results. Go back and try different parameters – each one will give different results. Such is the nature of admixture analysis – different utilities have different reference populations and algorithms. Don’t take any of them as gospel. Have a little fun and try the “Archaic DNA matches” to see how close you are to some ancient people, like Clovis man. Or try the “Are your parents related?” utility.
Comments to improve this post are welcomed.
Permission is granted to anyone who wants to include a link to this blogpost in their message to Matches just starting with GEDmatch.
[21B] Segment-ology: Getting Started with GEDmatch; by Jim Bartlett 20170919