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I recently received my DNA results matching 3 other people with a 1 step mutation. If I understand this correctly the MRCA will have been 17.5 generations ago or apprx. 435 years, if the standard for a generation is 25 years. Couldn't the MRCA have been as close as 200 years ago or less? I understand that mutations do not occur with regularity but rather irregularity.
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Yes. You have a 50% probability of having a common ancestor, which means half of the time it will not be within that time frame but within either a greater or lesser time frame. See the link to Understanding MRCA on the Family Tree web page. I didn't find the data for11/12 there, but the principle works for any distribution. The more identical markers, the shorter time to MRCA. But it is a curve, not a point, wiwth a range of time within which the mutation can happen. -
Re: One step mutation
Originally posted by billees
I recently received my DNA results matching 3 other people with a 1 step mutation. If I understand this correctly the MRCA will have been 17.5 generations ago or apprx. 435 years, if the standard for a generation is 25 years. Couldn't the MRCA have been as close as 200 years ago or less? I understand that mutations do not occur with regularity but rather irregularity.Comment
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