ИСТИНА

The karyology of species of sturgeon from the Russian Far East demonstrates that the karyotype of the Sakhalin sturgeon (Acipenser mikadoi) includes 262+4 chromosomes with 80 biarmed chromosomes and the number of chromosome arms (NF) 342+4, the karyotype of the Amur sturgeon (A. schrenckii) includes 266+4 chromosomes with 92 biarmed chromosomes and NF 358+4, and the karyotype of the kaluga (A. dauricus) consists of 268+4 chromosomes with 100 biarmed chromosomes and NF 368+4. These results prove that all western Pacific sturgeon species are from a tetraploid origin, based on a recent ploidy scale. This suggests that at least three polyploidization events have occurred during the evolution of Acipenseridae. However, if polyploid species originated by hybridization between diploid species, there may have been more polyploidization events in this group of fishes.