Changes of genetic parameters in successive gynogenetic generations and some calculations for carp gynogenesis

Open Access
Publisher Website
Google Scholar
Abstract
In artificial gynogenesis diploidization of the sperm activated zygote is achieved by retention of the second polar body and by this method perfectly normal and fully viable broods can easily be reared. Studying this form of propagation, we determined the coefficient of inbreeding (F), the fixation index (P) and the degree of genotypic identity (I) introduced for characterizing the isogeneity of gynogenetic populations with the help of the parameters of the probability distribution of meiotic recombination between the centromere and the genes. All three parameters were linear functions of the moments of the distribution of recombination probabilities. The theoretical relationships were investigated in the artificial gynogenesis of the carp. It appeared without exception that the progress of inbreeding made by gynogenesis largely depends on the distribution of the recombination probabilities of the genes. The rate of increase of the F value was more rapid only in the first few generations (2–5) compared to sibmating. The increase of the F value slowed in subsequent generations and fell significantly below the values obtained by sibmating. The degree of genotypic identity (I) is not as sensitive to the type of the distribution of recombination probability. In the case of gynogenesis, the value of I abruptly converges to l much more abruptly than in the case of sibmating. Used alone, gynogenesis does not enable the production of homozygous strains to any great extent. However, partly heterozygous, but isogenic, linea can be rapidly produced.