Some haplogroups that are rare (less than 10%) or absent in the controls exist at high frequencies within particular surnames: examples are hgA1a in R., E1a in Bray, G in Wadsworth, J2 in Ketley, T in Feakes, Q* in Mallinson, R1* in Northam, and R1a in Swindlehurst (Figure 2a). Attenborough provides the clearest signal of coancestry, with 87% of chromosomes belonging to hgE1b1b1, which is present at only 1% in controls.Of interest:
Direct analysis of Y-STR haplotypes in father-son pairs gives mutation rate estimates around 2.1 x 10-3 per STR per generation (Gusmão et al. 2005), while an
‘evolutionary’ rate based on diversity accumulated in specific lineages within
populations (Zhivotovsky et al. 2004) provides a rate some three times lower,
at 6.9 x 10-4.
We therefore chose to estimate a mutation rate by typing the 17 Y-STRs in a set of deep-rooting pedigrees totalling 274 transmissions of the Y chromosome, and with a mean pairwise separation within all pedigrees of 5.6 generations (Supplementary Figure 2). This gave a rate of 1.5 x 10-3 per STR per generation. Figure 5 shows
the mean and standard deviations of ages for a total of 74 clusters based on
One would need to look at the specific set of markers to derive a relationship between this "King & Jobling" (KJ) mutation rate, but it appears to be ~0.75 of the germline mutation rate. In the first post of my Y-STR series, I argued that Y-STR variance (not identical, but related to the ρ measure used here) accumulates at near the germline rate. The KJ estimate seems closer to the germline rate than to the ~0.3 (slow) Zhivotovsky et al. mutation rate. Note also that the age estimates for relatively young groups (first figure in this post) tend to be underestimates (1:1.17 for the youngest data point), which further supports the thesis that Y-STR diversity accumulates at near (but not exactly) the germline rate.
Note also that the time depth of British surnames is not too widely different from the populations used by Zhivotovsky et al. (Bulgarian Gypsies, Maori) for calibration of their evolutionary mutation rate. Therefore, it appears that the Zhivotovsky et al. rate is inconsistent with British surnames, and this underscores the difficulties with archaeological calibration of the mutation rate I talked about here.
Molecular Biology and Evolution doi:doi:10.1093/molbev/msp022
Founders, drift and infidelity: the relationship between Y chromosome
diversity and patrilineal surnames
Turi E. King and Mark A. Jobling
Most heritable surnames, like Y chromosomes, are passed from father
to son. These unique cultural markers of coancestry might therefore have a
genetic correlate in shared Y chromosome types among men sharing
surnames, although the link could be affected by mutation, multiple
foundation for names, nonpaternity, and genetic drift. Here, we demonstrate
through an analysis of 1678 Y-chromosomal haplotypes within 40 British
surnames a remarkably high degree of coancestry that generally increases as
surnames become rarer. On average, the proportion of haplotypes lying
within descent clusters is 62%, but ranges from zero to 87%. The shallow timedepth of many descent clusters within names, the lack of a detectable effect of
surname derivation on diversity, and simulations of surname descent suggest
that genetic drift through variation in reproductive success is important in
structuring haplotype diversity. Modern patterns therefore provide little
reliable information about the original founders of surnames some 700 years
ago. A comparative analysis of published data on Y diversity within Irish
surnames demonstrates a relative lack of surname frequency dependence of
coancestry, a difference probably mediated through distinct Irish and British
demographic histories including even more marked genetic drift in Ireland.