Effects of patterns of mating success and juvenile survival probabilities on rates of genetic drift

Aline Magdalena Lee, Steinar Engen and Bernt-Erik Sæther have come up with a good paper titled “The influence of persistent individual differences and age at maturity on effective population size’ in the journal Proceedings of the Royal Society B.

Ratios of effective populations size, N_e, to census population size, N, are used by scientists to measure genetic drift in populations. These ratios are affected by factors like mating system and age at sexual maturation. 

The researchers used a stochastic matrix model and examined how different levels of persistent individual differences in mating success among males may affect N_e/N, and how this relates to generation time. These differences are shown to cause a lower N_e/N ratio than would be expected when mating is independent among seasons. 

The researchers found that both the direction and magnitude of the effect depends on the survival rate of juveniles in the population. When maturation is delayed, lowered juvenile survival causes higher levels of genetic drift. Predicted shifts in N_e/N with changing age at maturity are shown to be dependent on which of the commonly used definitions of census population size, N, is employed.

The researchers clearly demonstrate that patterns of mating success, as well as juvenile survival probabilities, have substantial effects on rates of genetic drift.

Published online before print March 24, 2011, doi:10.1098/rspb.2011.0283 Proc. R. Soc. B