Vol 51(2017) N 2 p. 274-282; DOI 10.1134/S0026893317020121
D.N. Kamenskaya1, M.V. Pankova2, D.M. Atopkin2,3, V.A. Brykov1,2*
Divergence of paralogous growth-hormone-encoding genes and their promoters in Salmonidae1Federal State-Funded Institution of Science National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Science, Vladivostok, 690041 Russia
2School of Natural Sciences, Far Eastern Federal University, Vladivostok, 690012 Russia
3Institute of Biology and Soil Science, Far Eastern Branch, Russian Academy of Science, Vladivostok, 690022 Russia
Received - 2016-04-11; Accepted - 2016-09-08
In many fish species, including salmonids, the growth-hormone is encoded by two duplicated paralogous genes, gh1 and gh2. Both genes were already in place at the time of divergence of species in this group. A comparison of the entire sequence of these genes of salmonids has shown that their conserved regions are associated with exons, while their most variable regions correspond to introns. Introns C and D include putative regulatory elements (sites Pit-1, CRE, and ERE), that are also conserved. In chars, the degree of polymorphism of gh2 gene is 2-3 times as large as that in gh1 gene. However, a comparison across all Salmonidae species would not extent this observation to other species. In both these chars' genes, the promoters are conserved mainly because they correspond to putative regulatory sequences (TATA box, binding sites for the pituitary transcription factor Pit-1 (F1-F4), CRE, GRE and RAR/RXR elements). The promoter of gh2 gene has a greater degree of polymorphism compared with gh1 gene promoter in all investigated species of salmonids. The observed differences in the rates of accumulation of changes in growth hormone encoding paralogs could be explained by differences in the intensity of selection.
growth-hormone genes, nucleotide diversity, gene duplication, Salvelinus, Salmonidae, cis-regulatory regions