Genetic analysis carried out in population tails reveals diverse two-loci interactions as a basic factor of quantitative traits variation in rye

Bidirectional selective genotyping carried out independently for five quantitative traits within a biparental population of recombinant inbred lines of rye has revealed dramatic changes in alleles distribution in the population tails. A given allele, predominant in the lower tail, is often neutral for reversely directed selection or associates with the upper tail following divergent selection for a related trait. Such radical changes in the alleles distribution cannot be explained by differences in genotypic values within a single locus. This paper presents the theoretical model of a genetic mechanism underlying observed responses of individual loci to divergent selection. The presented model refers to the specific interactions between alleles at two loci. Its wider application in genetic analysis will open up new possibilities for testing positions of genes in the hierarchical structure of interacting loci revealed under selection pressure.