The second expansion occurred between 20 to 10 kya with Ne expanding to ~50,000, which was followed by a severe population reduction.
This is consistent with the long-term high effective population size and deep structure of autochthonous mtDNA haplogroups in South Asia76,77,78, in striking contrast to the severe population reduction affecting hg U7 during the last glacial period.
The results of these analyses suggest that the Mo-Singto population is moderately diverse (mean number of effective alleles across eight loci = 3.36, standard deviation = 1.78), is more-or-less in Hardy Weinberg equilibrium, and has not recently been subject to severe population reduction.
These observations suggest that the remnant populations we sampled have not had sufficient time to show the effects of severe population reduction (inbreeding and genetic drift), perhaps due to the long lifespan (300+ years) of post oak.
Also, nonadditive genetic variance may be converted into additive genetic variance during processes of severe population reduction, thus increasing additive genetic variance instead of decreasing it (e.g. Bryant et al. 1986; Fernández et al. 1995).
According to the out-of-Africa hypothesis of human origins, this can be explained by groups migrating out of Africa experiencing severe population bottlenecks that have resulted in a reduction in the genetic diversity in the descendant populations [ 22, 23].
Although most species on the IUCN Red List probably have experienced very recent and severe declines, it is important to note that our data demonstrate that many of them have also been subject to more long-term population reductions.
Several scenarios may explain this: i) the population reduction was not severe enough to impact the genetic diversity measures.
Using standard diversity indices, Bayesian skyline plot and approximate Bayesian computation, we detected a population reduction which was more prolonged than, but not as severe as, historic documents indicate.
