There is an updated Matching White Paper available from Ancestry.Ī very large percentage of small segments are not valid shared DNA, and half of the valid small segments are at least 20 generations old.Īs many of you have seen before, I call small segments “poison.” I equate them to poison chocolate-covered candies (because I love non-poisoned chocolate covered candies). This is the big one, and the focus of the remainder of this blog post! It may also affect the number of ThruLines you may see.” These changes to the matching algorithm will reduce the total number of DNA matches you have and the number of new matches you will receive. As a result, you’ll no longer see matches (or be matched to people) that share less than 8 cM with you – unless you have added a note about them, added them to a custom group or have messaged them. Matches that share 6 to 7.9 cM will be eliminatedįrom the announcement: “Our updated matching algorithm will increase the likelihood you are actually related to your very distant matches. Of course, the efficacy of this improvement depends entirely on the previous improvement, namely the ability to identify the true length of segments shared by a match.ģ. It will allow them to identify, to a degree, matches that share only small pieces of DNA (and thus much older common ancestry) and matches that share at least one large piece of DNA (and thus more recent common ancestry). This is a surprising change! Knowing the length of the longest segment shared with a match will be enormously beneficial to test-takers with endogamous ancestry. Our updated matching algorithm can show you the length of the longest segment you share with your matches.” Segment length is also the easiest way to evaluate the difference between multiple matches that all show the same estimated relationship. The longer the segment, the more likely you’re related. Length of the longest shared segment will be providedįrom the announcement: “The length of the longest segment you and a DNA match have in common can help determine if you’re actually related. We haven’t found the number of segments to be particularly useful evidence anyway, in most cases.Ģ. It will be interesting to see if the number is 23 after the update.
For example, I share 44 and 49 segments with my parents when in fact it should be exactly 23. In Genetic Genealogy Tips & Techniques, we’ve noted that the number of shared segments is usually inflated. This doesn’t change the estimated total amount of shared DNA (measured in centimorgans/cM) or the predicted relationship to your matches.” Our updated matching algorithm may reduce the estimated number of segments you share with some of your DNA matches. The number of shared segments should improveįrom the announcement: “The DNA you share with a match is distributed across segments – short segments, long segments, or some combination of both.The changes to the DNA match list comprise the following: The announcement started to appear on the DNA match list page yesterday:Ĭlicking on the link brings up information about the changes: There are significant changes coming to our DNA match list.
The AncestryDNA database has hit 18 million test takers (such great news!) and.During a phone call with AncestryDNA representatives this week (unfortunately I was not able to attend), numerous genealogists heard two major announcements: