Archives

A Really Basic Approach to Using GEDmatch

Feb18

GEDmatch.com is about to get a face lift. Many have complained that it is not intuitive and does not offer enough help for a newcomer. The new site hopes to correct some of that; I am helping with the beta test now; it sure is prettier!

Why use GEDmatch and what is it? Well it’s a free 3rd party site of tools where you can upload your DNA test results and compare them with those from people who have tested at other companies. Plus there are many analysis tools, some available nowhere else. These include GEDCOM (family tree) comparisons, including yours to your DNA matches.

Recently I gave a talk for the Family History Fanatics at their Winter of DNA conference where I demonstrated how to use GEDmatch without worrying about segments. An approach that gets a lot out of the site without having to be a geek like me. The slides are here: https://slides.com/kittycooper/gedmatch-basics-2021

Here is a step by step of that very basic approach as outlined in the syllabus for my FHF presentation

1. Create a User ID and Upload a DNA raw data file, aka a “kit”

Click the image above to go to the video from Andrew Lee, of FHF, which shows you how to create a user id and upload your DNA raw data to GEDmatch.

Or read this blog post of mine which also has links to my other GEDmatch posts
https://blog.kittycooper.com/2019/02/genesis-basics-gedmatch-reinvented-part-1/

2. Once Logged in, your Dashboard Page is not Intuitive

The tools are in the right hand column and the resources you have uploaded are listed on the left. You can upload more than one DNA kit and multiple GEDCOMs. There is a help section on the top right.

This post from Jim Bartlett is a useful explanation of the home page, as is my basics post listed above.
https://segmentology.org/2018/05/01/first-time-at-gedmatch/

And here is what my beta test Dashboard looks like, an improvement? I think so.


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Can Y DNA Solve an Unknown Parentage Case?

Jan10

Sometimes testing the Y chromosome can help when you are looking for a missing father, grandfather, or further back as long as you have a tester descended on the male only line. Remember the Y is passed father to son, so any changes are rare and are caused by mutations not recombination. Typically a man would start with a Y 37 STR marker test at Family Tree DNA to see if this avenue is worth pursuing. A STR test gets the most recent changes rather than the haplogroup, thus can suggest a surname. Click here for my article explaining Y testing.

Slide from my 2017 talk on DNA testing for genealogists featuring my maternal grandad

The Y results will not help if no other men from that Y lineage have tested unless you have a theory. In that case you need to test someone else descended on the male only line from the presumed ancestor.

Y testing can be very useful when the unknown parentage occured many generations ago, such that autosomal testing may not be able to solve it.

If your ancestors have been in the USA for some time then a Y 37 STR marker test may find a probable last name. In that case there may be a surname project with other Y testers at Family Tree DNA. I recommend contacting the admins of that project as they can often be a great help in your quest. However if you are from a population group which has only had inherited surnames for two hundred years or less, quite likely you will have no luck.
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Family History Fanatics Winter DNA Conference!

Jan1

I will be doing a talk on GEDmatch Basics for the Family History Fanatics (FHF) Winter DNA Conference. UPDATE: 25 Jan 2021: I have received screen shots of the new look coming soon to GEDmatch; these will be featured in my presentation.

They also have a youtube channel (click here). Here is the Press release from FHF:

KICK OFF THE YEAR RIGHT

Saturday, 30 January 2021 beginning at 9:45 AM Eastern Time.
If you can’t attend the event during the live sessions, you’ll have access to the replay for 30 days.

TOPICS & PRESENTERS

  • DNA & Law Enforcement – Marian Woods
  • GEDmatch Basics – Kitty Cooper
  • Tracing Ancestral Lines in the 1700s Using DNA – Tim Janzen
  • A Guide To Chromosome Browsers & DNA Segment Data  – Michelle Leonard

 AFTER THE SESSIONS

The four panelists will return for a “test your knowledge’ competition and then more of your unscripted rapid-fire questions. 

Early bird pricing is $19.99 until January 22nd. After that, pricing will increase to $24.99. 

When you register, you’ll be entered to win genetic genealogy-related door prizes. 

To learn more and register visit, www.familyhistoryfanatics.com/winterdna. 

Family History Fanatics is a genealogy education company that is focused on putting the fun into online learning. See the difference the FHF Group puts together for you.

Goodbye Yahoo Groups

Dec16

Yesterday, December 15, was the last day of Yahoo groups. Those mailing lists were places where we could ask questions and be answered by others who had already solved similar problems. We also got news about things of interest to the particular group we were following.

Yes there was plenty of notice that this would happen, but still, I was not really ready, were you? Most of the groups I belonged to sent me emails telling me where they had moved to, often long ago. The top two providers chosen were Google Groups and Group.IO – you can always search each of them for your old group name and then sign up again when you find it.

However, much of that asking for help activity has long since moved to FaceBook. Personally I prefer the old style mailing lists because it is easier to find what I am looking for in their archives. Maybe I am just too 20th century still.

For genetic genealogy there is a list of Facebook groups and mailing lists at the ISOGG wiki here:
https://isogg.org/wiki/Genetic_genealogy_mailing_lists_and_Facebook_groups

Here is a list of the mailing lists I follow at their new homes:
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ALERT – Bug in the GEDmatch “Are Your Parents Related Tool”

Dec12

UPDATE: 13-Dec-2020: FIXED! The code had not changed but the environment had, so an initialization was different. Thus my analysis that it was always the first few chromosomes helped the programmer solve the issue.

 

The “Are Your Parents Related Tool” (AYPR) has been an enormous aid to those adoptees who discover that they were a result of an in-family relationship. Thus it is very distressing to have gotten a report from a reader that the tool is suddenly showing less cM that are ROH than it used to.

My investigation has shown that the first few chromosomes have segments that are not marked as ROH when they should be and were in previous versions. The programmer who can fix this told me that this bug goes back perhaps as far as this past summer He does have a working copy from July, but is in the middle of a major new project. Thus he may not be able to attend to this until later this coming week,

In the meantime, here is an example of how this looks so you can try to make your own estimate. The results for a child of first cousins was shown in my blog post about this tool (click here for that post).

ROH for child of first cousins,  buggy version on left, previous correct version on right (click for larger version)

To the left is how that looks now, while on the right is how it looked last year. Notice that the first three chromosomes on the left have not been included in the ROH listing. Also, the previous total was 215.3 which, when multiplied by 4, fit the first cousin scenario, now confirmed. The total without those first few chromosomes today is 126.8.

The cases from closer relations are even further off. A child of siblings had 744cM ROH last year but now gets only 465.6. A child from a father daughter pairing was was 750.4 and is now 547.9. In both cases the problem was the first four or five chromosomes were not having their ROH segments counted any more.

I will post an update on this blog post once the issue is fixed.