Saturday, January 17, 2015

If you still have questions about autosomal DNA...

Check out, and study, Roberta Estes' blog today:

One caution: Roberta talks a lot about IBS (identical by state, as opposed to IBD -- identical by descent) matches. While virtually all matches at all three companies are IBD and therefore reliable matches to your relatives, those with really small amounts of matching DNA may not be. Accept the matching thresholds and you're safe to assume the matches are real. If you tinker with the thresholds, i.e., lower the matching level, then beware. The only time you should ever lower the level is when you believe an individual should match you but doesn't, then give that a try -- but only if you have good reason to believe the other person is a definite relative.

One example of this might be if your sibling or a cousin matches someone and you don't, you might want to try lowering the threshold to see if you inherited such a small chunk from the common ancestor that it simply doesn't show up. Of course, there's always the possibility that you didn't inherit any from that particular ancestor.

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