The structure of the Baikal population of Cyclops kolensis.Lill, 1901 (Copepoda, Cyclopoida) and phylogenetic relationships with some non-Baikal representatives of the species based on the molecular genetic analysis of the mtDNA CO1 fragment

Abstract

We studied the population structure of the Cyclops kolensis.Lill, 1901 copepod in Lake Baikal. For analysis, we used the fragment sequences of the cytochrome oxidase subunit 1 (CO1) of mitochondrial DNA. Based on these sequences, we constructed a haplotype tree for Baikal individuals as well as a phylogenetic tree for the sequences of Baikal and non-Baikal members of C. kolensis using the molecular clocks. In general, the distribution of haplotypes across the lake basins indicates the absence of geographical subdivision, although there are traces of the past local isolations as well as possible recent introductions from the water bodies near Lake Baikal. We have determined the time of the divergence between the Baikal representatives and the European ones (from the lakes of Moscow and Kiev), which dates back to 1.13 million years (95% CI: 0.67-1.63 million years). The divergence of the Baikal group of haplotypes is 0.31 million years (CI: 0.16 - 0.48 million years), which may be the time when the species entered the lake.