Adaptive evolution signals in mitochondrial genes of Europeans

Abstract

Since modern Europeans appear to be descendants of the Late Pleistocene European peoples who survived the last glacial period, it is quite reasonable to expect the presence of adaptive genetic variants that originated in the Ice Age in the modern gene pool of Europeans. To find such adaptive variants, mitochondrial genomes have been analyzed of the modern population from Eastern and Central Europe belonging to haplogroups U4, U5, andV, that diversified during the Late Pleistocene and Holocene periods. Analysis of distribution of nonsynonymous and synonymous substitutions, as well as results of search for radical amino acid changes that arose under the influence of adaptation (positive destabilizing selection) allowed us to detect signals of molecular adaptation in different mitochondrial genes and haplogroups of mtDNA. However, there were very few strong adaptive signals (z > 3.09, P < 0.001) that could be due to the loss of adaptive mtDNA haplotypes during the Holocene warming.