Gonadal analysis in the F1 progeny of a gynogenetic Siberian sturgeon Acipenser baerii female.

This is the first report of reproduction of a gynogenetic female Siberian sturgeon (Acipenser baerii) and subsequent production of viable offspring with differentiated gonads. Gonads were sampled twice from 30 randomly selected individuals. Gonadal fragments were examined histologically to identify the sex ratio and the sexual maturation stage. The first examined group consisted of 20 % females, 45 % males and 35 % sexually undifferentiated individuals, whereas the second group was composed of 30 % females and 70 % males. The average gonadosomatic index was determined to be 2.72 % and 2.80 % in the first and second groups, respectively. Molecular analysis based on five microsatellite DNA loci was conducted for all the fish for which there were evaluations. The aim of the study was to determine whether the gynogenetic Siberian sturgeon female that produced the offspring that were evaluated was a "superfemale" (WW) or a normal female (ZW). A "superfemale", therefore, is a female of the WW genotype that will produce only females when mated to a male with a ZZ genotype. The presence of female and male offspring clearly indicates that the Siberian sturgeon female that produced the offspring was not a "superfemale".