The impact of founder events on chromosomal variability in multiply mating species.
In species with heterogametic males, the relative levels of X chromosome versus autosome diversity hold key information about the evolutionary forces at work in a population. It has been shown that population size changes alter the ratio of X linked to autosomal (X/A) variation, with population size reductions and recent bottlenecks leading to decreased X/A diversity ratios. Here we use theory and simulation to investigate a separate demographic effect-that of founder events involving multiply mated females-and find that it leads to much stronger reductions in X/A diversity ratios than are produced by simple population size changes. Investigating the potential of this process to account for sharply reduced X-linked diversity in European Drosophila melanogaster, we find that this model yields predictions that are compatible with the empirical data.
Department of Integrative Biology, University of California, Berkeley, USA. jpool@berkeley.edu
John E
JE
Pool
Rasmus
R
Nielsen
D000818:Animals; D002875:Chromosomes / Q000235:genetics*; D003198:Computer Simulation; D004331:Drosophila melanogaster / Q000235:genetics* / Q000502:physiology; D005260:Female; D018703:Founder Effect; D050172:Genes, X-Linked / Q000235:genetics*; D014644:Genetic Variation; D005828:Genetics, Population; D008957:Models, Genetic; D012726:Sexual Behavior, Animal / Q000502:physiology*