Shedko S.V., Miroshnichenko I.L., Nemkova G.A.
В журнале Russian Journal of Genetics
Год: 2020 Том: 56 Номер: 6 Страницы: 718–724
Natural hybridization of sturgeon species in sympatry area is a relatively frequent but poorly studied phenomenon. A unique picture of asymmetric hybridization for Acipenseridae has developed in the Amur River, the place of inhabitation of two endemic sturgeons of this river basin—Kaluga and Amur sturgeon. Earlier, we showed that the fraction of their hybrids in different years was about 2.5% of the abundance of parent species. All analyzed hybrids carried only one type of mtDNA—Kaluga. However, the identification of hybrids and pure individuals in this study was based on consideration of only external morphological characteristics. In the present work, the set of genetic markers was expanded to include six nuclear loci in the analysis: two introns of the ribosomal protein L8 (RP4L8, RP5L8) and microsatellites An20, Afug41, HLJSX37, and HLJSX350. As a result, it was shown that all morphologically intermediate individuals, previously classified on this basis as hybrids, for each of the nuclear loci had a mixed composition of alleles characteristic of both Kaluga and Amur sturgeon. Among those individuals which by external morphology were identified by collectors as Kaluga, there were identified three individuals that should be classified as hybrids according to their genetic characteristics. In addition, four other individuals were classified as backcrosses to Kaluga. All hybrids and backcrosses had Kaluga mtDNA type, which confirms the earlier conclusion about unidirectional hybridization of Kaluga and Amur sturgeon in nature: Kaluga (♀) × Amur sturgeon (♂). The used set of markers has the necessary resolution and can be recommended for the identification of pure Kaluga and Amur sturgeon and their hybrids. The minimum set of markers for diagnosis includes mtDNA, introns RP4L8 and RP5L8, and microsatellite HLJSX37.
