Friday, June 23, 2017

A Helpful DNA Relationship Chart (Especially for AncestryDNA Users) - Shared cM Project Chart

Blaine Bettinger's shared cM chart available at the Autosomal DNA Statistics page of the International Society of Genetic Genealogy Wiki.  I use this all the time when I am analyzing my AncestryDNA matches.

Although AncestryDNA refuses to offer a chromosome browser, they do offer some helpful bits of information.  You can't see where you share DNA with any given cousin match, but you can see the total cM shared and how many segments shared.

A typical scenario: no tree, no chromosome browser, but at least I can see that Ancestry is confident of this match and it tells me how much DNA is estimated to be shared.  AncestryDNA estimated 4th cousin (avg 31 cM shared according to chart above), but it could be anything from a 1st cousin 2x's removed to a 4th cousin 1x's removed, but too much for a 5th cousin (unless there are other people you share that you don't know about).

This chart is very helpful to immediately determine a likely set of possible relationships.  I like that it includes both the average amount shared as well as includes the range of possible shared cM.

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