Wednesday, June 4, 2014

DNA News Update: Genome Mate's Segment Mapper

Kitty's segment map

Genome Mate now allows you to download a CSV file to Kitty's DNA mapper site.You can also use the mapper provided at the Genome Mate site itself. This is an important tool to keep track of your shared segments. Autosomal DNA, for genealogy, is all about the finding shared segments. Matching segments establishs a genetic relationship between you and your matches. Triangulation is an important part of genetic genealogy because it allows you to find matches who share segments in common with you and your matches. Sharing DNA on a small random segments with another person doesn't prove you are related to them. To confirm a relationship you need to find a shared ancestor. The best proof is having a shared ancestor with your match, and more than two people from the same line matching on the same segment, or segments. CeCe Moore gave more clarification regarding her statement about sharing multiple segments, and its implication that you share a common ancestor more recently. She said the segments should be larger ones; 7 cMs and over. Although there isn't any hard and fast rule regarding how much DNA anyone past 3rd cousin should share in order for the match segments to be IBD.

The segments maps at Genome Mate and Kitty's Mapper are both great. You can download a CSV file from Genome Mate with your selected segments. This is great. Otherwise you would have to select the matches 5 at a time from Family Tree DNA's chromosome browser, or slowly copy them off a spreadsheet. Both more time consuming. Before you upload the file you can open it and change the segment names if you would like (you actually do need to open the file anyway to rename the segment headings Start and End).

All of Genome Mate's tools are very helpful. It's an indispensable program for Genetic Genealogy.

CSV file

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