Pukhtayevych P. Karyotype variability and structure of hybrid diploid–polyploid complex of fish of the genus Carassius Nilsson, 1832 and Cobitis Linnaeus, 1758 of the Rightbank Polissya of Ukraine.

The dissertation is devoted to the study of the structure of hybrid diploid-polyploid complex of fish of the genus Carassius and of the spined loaches Cobitis - Sabanejewia in water systems of the Rightbank Polissya of Ukraine based on the analysis of cytogenetic and allozyme data. Presented are the results of cytogenetic and allozyme analysis of the diploid Carassius: C. auratus and C. сarassius, a range of tryploid biotypes С. gibelio, diploid hybrids С. auratus - C. carassius and tetraploid C. carassius - С. gibelio-1. Identified are 20 biotypes of silver Prussian carp С. gibelio, which were structured in a certain way. Determined are the karyotypes of the three most popular among them. Analysis of karyotypes and genotypes of constant heterozygote spectrum made it possible to establish the possible origin of various clonal lines of tryploid representatives of C. gibelio. Described are the karyotypes and conducted is an allozyme analysis of the genus Сobitis and Sabanejewia, including diploid Сobitis taenia and Sabanejewia aurata, tryploid biotypes: С. elongatoides - 2 taenia, С. elongatoides - taenia - tanaitica, С. 2 elongatoides - tanaitica and intrageneris hybrids C. taenia - C. tanaitica - S. aurata and С. taenia - Sabanejewia aurata. The obtained data gives the reason for the hypotheses concerning the origin of complex hybrid involving the golden loach. Proposed are three possible ways of formation of triploid hybrid biotype C. taenia - C. tanaitica - S. аurata. Discussed are the issues of characteristics of the genetic structure of fish habitats of prussian carp and spined loaches of the Rightbank Polissya of Ukraine. Presentes are the data of comparative analysis of own materials with information on other ponds from regions of Ukraine.