The increased rate of fixation of nucleotide substitutions in mitochondrial DNA in bony fish (Osteichthyes) species that originated in the Arctic or dispersed through it
V. S. ARTAMONOVA1, A. Yu. ROLSKII2, M. V. VINARSKI3, A. A. MAKHROV1,3
1Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences, Moscow, Russia
2Russian Federal Research Institute of Fisheries and Oceanography, Murmansk, Russia
3Saint Petersburg State University, Laboratory of Macroecology and Biogeography of Invertebrates, Saint Petersburg, Russia
Keywords: Polar ecosystems, natural selection, saltations, median networks, Arctic ocean
Abstract
The problem of differences in the rates of evolution among different species of animals and plants has been discussed very intensively in recent years, and, in connection with this, the question of whether the so-called molecular clock hypothesis is valid is acutely raised. We conducted a search for scientific papers providing median networks that include mitochondrial gene haplotypes for closely related boreal and Arctic (or dispersed through the Arctic) fish species. In all seven cases analyzed by us, in Arctic taxa or taxa that passed through the Arctic during their phylogeny, the rate of nucleotide substitutions was higher, and this difference, as it turned out, is statistically significant. Thus, the formation of new fish taxa in polar latitudes is accompanied by rapid evolution of mitochondrial DNA, which, apparently, is the manifestation of their adaptation to a new habitat. In addition, speciation in fish in the Arctic is usually accompanied by multiple chromosome fusions. Thus, both our and the literature data give new strong reasons to doubt the validity of the molecular clock hypothesis.
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