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From: "Charles Acree" <>
Subject: [DNA] MRCA Estimates
Date: Wed, 10 Feb 2010 11:52:54 -0600


Spirited discussion of the value and methodology of Most Recent Common Ancestor (MRCA) statistical inference is worthwhile because those estimates can be helpful, particularly with regard to pre-historic times. However, as we all know, MRCA predictions can often mislead when applied to the genealogical time-frame (roughly the past millennium).

In our Acree surname project, for instance, MRCA statistics have proven totally inapplicable. Of the nineteen of us (mostly and impressively, 4th-8th cousins) who descend from a common Acree ancestor born 300 years ago (affirmed by genealogical documentation), none of us has a genetic distance (GD) from the mode greater than two, and all of us share the distinguishing, invaluable partial-repeat at DYS385b that I've mentioned. Seven of us match 46/46 (by Ancestry.com's count); five match 45/46; and six match 44/46. (The nineteenth matches 12/12.)

Two participants have an uncle/nephew relationship. Guess what their match is. No, you got it wrong. The uncle is one of those who matches the mode 44/46 - differing from his nephew in two (fast-mutating) markers (GD=2, one up, one down).

Charles Acree



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