Geographic variations of melanocortine 1 receptor gene (MC1R) in the common frog (Rana temporaria) in Northern Europe

Abstract

The melanocortin 1 receptor (MC1R, or MSH receptor) of melanophores (pigment-containing cells) receives pigmentation signals from the pituitary, and is likely to play a crucial role in the background color adaptation and the dorsal pigment patterning in amphibians. As such, these genes are likely to be under strong selection at particular habitats and at the same time exhibit geographic variations by neutral substitution at other habitat within species. To investigate geographic clines in the MC1R gene variability in the common frog (Rana temporaria), the coding region sequence was analyzed across Northern European populations. Interestingly, the two colonization routes in Fennoscandia (Eastern and Western) showed different evolutionary stories regarding the MC1R gene. Higher variation in both nucleotide and predicted amino acid sequences were found on the Eastern as compared to the Western side of Fennoscandia. The variation in Western Fennonscandia was very low and nearly mono-allelic. This result is consistent with a recent and rapid recolonization from the South (Denmark), and/or strong selection on one favorable allele in the western side of Fennoscandia. © 2012 Koninklijke Brill NV, Leiden.