The Value of a DNA Segment

 Hi folks, if you saw my post last week, Wikitree, and the Value of Half-Relatives then you know that I was excited to know that the one DNA segment that my mystery match and I shared was from one shared ancestor, my second great-grandfather Elias Henry Baysinger. 

Elias Henry Baysinger 1832-1900

Elias married three times and had 15 children, one of whom died at birth or within days of birth and is buried in the same grave as my second great-grandmother Sarah who was the second wife and mother of ten. 

My match descends from the third wife, Lydia, so the shared segment comes only from Elias, and from neither wife. 



What can I do with this segment data beyond "painting" it?


Gedmatch Free Tools

The first tool I used was at Gedmatch, called People who match both kits, or 1 of 2 kits, a free tool. I often use this kit to find out who a mystery match is, because as the ungainly title of the tool says, it creates a list of those kits who match both kits. If some recognizable names pop up there, I usually know, at the very least, whether the match is on my father's or mother's side of my tree. 

In this case though, it gave me a list of Baysinger matches and some or all of them will be EH Baysinger matches! Click for the spreadsheet I created from that output; read-only. You can put in the kit numbers into Gedmatch to see what the raw output is like, and from there one can do further processing on the common matches, put them into a Match Group, etc. 


Gedmatch Tier 1 Tools ($)


What seems most useful in this case though is the Segment Search, which has an arrow in the image to the left.

Tier 1 costs $10 for a month, and I think a bit less if you auto-renew, which is what I do. If you don't use Gedmatch often, pay for a month occasionally when you need one of the tools. They are pretty cool, especially the Combine multiple kits into 1 superkit, which I have done. This allows slightly better SNP matching, since each auDNA testing company chooses a slightly different range of SNPs to test. After creating the "superkit" you can set your others for research only so each one will not show up multiple times in your match's searches.


Segment Search ($)

With the segment search, I can winnow the spreadsheet down to those who share the segment of interest. If you learn better from watching a video before trying it out, watch this short Family History Fanatics video first: Searching for Segments on GEDmatch - A Segment of DNA. I re-watched it before linking it here, and although it's two years old, it is still current information. The ancestor projects referred to at the end are growing and thriving, and are 100% free. There are 709 groups now. 


The Process

The match and my uncle share one segment on chromosome 14, from 57,309,063 to 90,451,500, so on the segment search, I asked only for chromo-14 from 57,000,000 to 90,000,000. By rounding off the numbers I hope to catch all the reasonable shared segments. A reminder that each of these matches must still be submitted to a one-to-one match test, to be sure that it truly is the same segment of DNA, and not on the maternal strand rather then the paternal. Remember that although the companies portray our chromosomes as line with segments, in reality it is two strands, one of which we get from our mother, and one from our father. Just because numbers match up does not mean anything unless there is a true match!


Segment Findings

In the graphic part of the output you can see the top large segment which the match shares with my uncle. I wonder if the smaller matches are further up the Baysinger tree. Only genealogy research can answer that question. First, I need to check each kit against my match and my uncle and see if they are a true match - they all are, and many of the larger matches share other segments with the match. I have not yet done a similar one to one with my uncle's kit. The output is saved to a spreadsheet so more analysis can be done. Some kits may have trees or other information which can assist in the search for common ancestors. 

Genealogy work continues!


Valorie Zimmerman


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