5000 years of molecular evolution in a population of the land snail Albinaria caerulea transported by humans

Abstract

Patterns of genetic variation of Albinaria caerulea, a land snail that was probably transported by humans to Vravrona (Attica, Greece), were analysed using the mitochondrial ATPase8 gene. The analysis of molecular variance indicated significant local differentiation at the subpopulation level. This considerable population subdivision and genetic differentiation in a short time is possibly related to life history and population structure of the species. The population structure and demographic history suggest a recent single colonization event, by a single or a few lineages, at the first site inhabited by humans in Vravrona (about 5,000 years before present). This was followed by population expansion and subsequent intra-colonization events (accompanied by bottlenecks) to more recently inhabited sites. The estimated small effective population size/census population size ratio further implies considerable population fluctuations. Bayesian inference and statistical parsimony analyses indicate that the population of Vravrona is associated with a species subgroup which includes populations found in the Cycladic islands of Sikinos, Folegandros and Thira; its source is probably related to certain samples from Sikinos.rved.