The aim of the study is to analyze the dynamics of two conditional alleles of ancestral forms (Ak and Am). Objectives: to study the frequencies of the Ak and Am alleles over several generations based on pedigree analysis; to study their dynamics using regression analysis methods; to analyze heterozygosity and relative fitness. The characteristics of such an indicator as "blood share" were studied. This indicator can be considered as an individual quantitative characteristic of an individual. On the other hand, it is the probability of transmitting an allele of an abstract locus over several generations from parent to offspring. In this case, the "blood share" is a qualitative trait, which was used in this study. The working hypothesis was that the large and small forms of domestic pigs, which are the ancestors of the minipigs breeding group of the Institute of Cytology and Genetics SB RAS, were carriers of two different alleles (Ak and Am) of the conditional locus A, which is understood as a gene complex that determines the live weight and body size of an adult individual. In the reproductive core of the herd, the distribution of genotypes for the conditional locus A does not conform to the Hardy-Weinberg law (generations 8–16). The discrepancy between observed and expected frequencies increases until the middle of the study period (the 12th generation). After passing the maximum point (starting with the 13th generation), the discrepancy gradually decreases. The discrepancy between the expected and observed patterns is caused by an excess of heterozygotes. Moreover, there is a pronounced deficiency of homozygotes for the large-form allele of domestic pigs. The stable ratio of allele frequencies at the conditional locus A over nine generations suggests that the study population is in a state of stable equilibrium, driven by the advantage of heterozygotes during selection into the reproductive core. Apparently, it is precisely due to the advantage of the heterozygous genotype that the large-form allele is preserved in the breeding group.
Nikitin et al. (Fri,) studied this question.