Thermal adaptation of Japanese sand lance (Ammodytes personatus) in different ocean currents revealed by the cytochrome-b gene

Abstract

To assess the possible thermal selection on mitochondrial coding genes in cold water species, we explored the population structure of Japanese sand lance (Ammodytes personatus) and performed selection tests on the mitochondrial cytochrome-b gene of species, using 174 individuals from eight different sea temperature populations in different ocean currents. Two distinct haplotype lineages were present in this species, and the lineage frequencies varied with changes in sea temperature. The selection tests showed that A. personatus was subject to purifying selection. Populations living in cold climates had a considerably smaller non-synonymous substitution rate/synonymous substitution rate (dN/dS) than those in temperate areas. The efficiency of the electron transfer chain system may be affected by amino acid changes at codons 353 and 371. These findings provide new evidence that temperature may affect the contemporary distribution of mitochondrial DNA clade frequencies in A. personatus.