[Diploid radiation-induced gynogenesis in carp. II. Segragation according to morphological traits in gynogenetic...

The character of segregation in diploid gynogenetic progenies of Cyprinus carpio with respect to the following three external characters was studied: the type of scale cover, the colour and the design. The genetic formulae of these characters are as follows: the type of scale cover: scaled--(Snn); scattered--(ssnn); linear--(S--Nn); nude--(ssNn); the existence of design (D--); the absence of design--(dd); the type of colour: light--(LI); dark--(II). The dominant genes N and L exert a recessive lethal effect. For the loci N--n, D--d and L--l a conspicuous prevalence of dominant form was established. Linear and nude carps constituted 98%, light carps--85% and carps with a design--also 85% of the total number of gynogenetic descendants. The proportions of heterozygotes Nn, Ll and Dd were 97.3, 73.9 and 70.0% respectively. The frequencies of descendants dominant and recessive for the locus S--s proved to be closely similar: 52.4% (S--) and 47.6% (ss)the proportion of heterozygotes Ss being 4.8%. The data on the frequency of gynogenetic heterozygotes suggest the existence of a high positive interference in the carp. The value of the latter for the four loci studied, the genetic distance between each of these loci and "its" centromere was determined. The data obtained are discussed.