I guess there's room for doubt about this conclusion because, just based on the visible differences between haplotypes, Group B is only just barely more remotely related to Group A than Donor C is to Donor A. Like only 100 years more remotely, not the ~350 that I concluded.
I figured the reason companies don't offer clear guidance about predicting relationships past GD of 6 at 67 is because of an increased chance of masking mutations when the number of mutations >10% of the total number of markers. That is, the larger mutations are as a proportion of the number of markers, the higher the chance that the next mutation over-writes an existing one, or mimics the haplotype of a cousin's lineage.
So I calculated the probability distribution of X number of masking mutations for each generation's removal from the common ancestor, and recalculated a confidence interval for the relationship accordingly. That's reflected in the figures I quoted in my last post.
This narrow, 15-year overlap in the 50% to 95% confidence intervals of the B-A and B-C comparisons that I talked about was only enabled by this assumption of a number of masking mutations. In other words, I'm talking about an only 5% scenario. Very tight. Not implausible--one in twenty are not crazy odds. But very tight.
To me, this suggests a fairly specific mutation scenario, where the ancestors of the Group A experienced 3 mutations which coincidentally mirrored those experienced by Group B.
I'm thinking these were probably DYS390, DYS464C and DYS 476, experienced by Group A in the years after they branched off from Dorey but before they branched off from one another--roughly between 1350 and 1600 A.D. A little fast, but plausible.
The time frame for Group B experiencing these same mutations might be inferred by both members' identical genetic distance to Donor C, roughly between 1000 A.D. and 1600 A.D.
I wish there were a wider margin of error in this case, but this is just the way the numbers line up. I guess this is why the company doesn't express much confidence about genetic distances in this range.
I figured the reason companies don't offer clear guidance about predicting relationships past GD of 6 at 67 is because of an increased chance of masking mutations when the number of mutations >10% of the total number of markers. That is, the larger mutations are as a proportion of the number of markers, the higher the chance that the next mutation over-writes an existing one, or mimics the haplotype of a cousin's lineage.
So I calculated the probability distribution of X number of masking mutations for each generation's removal from the common ancestor, and recalculated a confidence interval for the relationship accordingly. That's reflected in the figures I quoted in my last post.
This narrow, 15-year overlap in the 50% to 95% confidence intervals of the B-A and B-C comparisons that I talked about was only enabled by this assumption of a number of masking mutations. In other words, I'm talking about an only 5% scenario. Very tight. Not implausible--one in twenty are not crazy odds. But very tight.
To me, this suggests a fairly specific mutation scenario, where the ancestors of the Group A experienced 3 mutations which coincidentally mirrored those experienced by Group B.
I'm thinking these were probably DYS390, DYS464C and DYS 476, experienced by Group A in the years after they branched off from Dorey but before they branched off from one another--roughly between 1350 and 1600 A.D. A little fast, but plausible.
The time frame for Group B experiencing these same mutations might be inferred by both members' identical genetic distance to Donor C, roughly between 1000 A.D. and 1600 A.D.
I wish there were a wider margin of error in this case, but this is just the way the numbers line up. I guess this is why the company doesn't express much confidence about genetic distances in this range.
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