Genetic divergence and isolation by thermal environment in geothermal populations of an aquatic invertebrate
2016 (English)In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 29, no 9, 1701-1712 p.Article in journal (Refereed) Published
Temperature is one of the most influential forces of natural selection impacting all biological levels. In the face of increasing global temperatures, studies over small geographic scales allowing investigations on the effects of gene flow are of great value for understanding thermal adaptation. Here, we investigated genetic population structure in the freshwater gastropod Radix balthica originating from contrasting thermal habitats in three areas of geothermal activity in Iceland. Snails from 32 sites were genotyped at 208 AFLP loci. Five AFLPs were identified as putatively under divergent selection in Lake Myvatn, a geothermal lake with an almost 20 degrees C difference in mean temperature across a distance of a few kilometres. In four of these loci, variation across all study populations was correlated with temperature. We found significant population structure in neutral markers both within and between the areas. Cluster analysis using neutral markers classified the sites mainly by geography, whereas analyses using markers under selection differentiated the sites based on temperature. Isolation by distance was stronger in the neutral than in the outlier loci. Pairwise differences based on outlier F-ST were significantly correlated with temperature at different spatial scales, even after correcting for geographic distance or neutral pairwise F-ST differences. In general, genetic variation decreased with increasing environmental temperature, possibly suggesting that natural selection had reduced the genetic diversity in the warm origin sites. Our results emphasize the influence of environmental temperature on the genetic structure of populations and suggest local thermal adaptation in these geothermal habitats.
Place, publisher, year, edition, pages
2016. Vol. 29, no 9, 1701-1712 p.
amplified fragment length polymorphisms, gene flow, landscape genetics, Radix balthica, temperature, thermal adaptation
IdentifiersURN: urn:nbn:se:uu:diva-306760DOI: 10.1111/jeb.12902ISI: 000384424500005PubMedID: 27208484OAI: oai:DiVA.org:uu-306760DiVA: diva2:1044523