New study finds difference in STR mutation rates based on Y haplo

www.sciencedirect.com/science/article/pii/S1872497318300206


Highlights

•The genealogical pair method enables to efficiently estimate Y-STR mutation rates.

•Y-SNP haplogroup differences in Y-STR mutation rates were observed.

•Haplogroup specific Y-STR mutation rates are caused by allele size differences.

•Y-STR mutation rate differences have an impact on tMRCA estimations


R1b STRs mutate faster than others, thus pulling up the average due to high occurrence.

I and J haplogroups have significantly lower mutation rates compared to R1b. This has been anecdotally noticed in the I1 Z63 research group who have been getting contradicting results of TMRCA when using STRs vs SNPs.

"Significant differences in average Y-STR mutations rates were observed when haplogroup ‘I & J’ (4.03 × 10−3mutations/generation) was compared to ‘R1b’ (5.35 × 10−3 mutations/generation) and to the overall mutation rate (5.03 × 10−3mutations/generation). A difference in allele size distribution was identified as the only cause for these haplogroup specific mutation rates."



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That is not surprising. Mutations happen more frequently in a large population than in a smaller one. R1b is not only the most common Y-haplogroup in Europe in terms of percentages, but by far the most numerous in terms of total numbers of individuals, as R1b is especially common in countries with high populations (UK, Benelux, France, Spain, northern Italy, western Germany...).

Maciamo said:

That is not surprising. Mutations happen more frequently in a large population than in a smaller one. R1b is not only the most common Y-haplogroup in Europe in terms of percentages, but by far the most numerous in terms of total numbers of individuals, as R1b is especially common in countries with high populations (UK, Benelux, France, Spain, northern Italy, western Germany...).

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While I agree that more carriers facilitate more total mutations, the difference is on an individual level. Each R1b man has a 24.8% higher chance than an I or J man of a STR mutation within one generation.

I'm not sure if this effect has been taken into effect by large companies such as FTDNA that offer age estimations based on STR differences.

If you are I1 and they estimate 500 years to MRCA, it would probably be 600 years unless they have already factored in the different mutation rate.

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