epigenetic mechanism of the effect of mildly deleterious mutations on the viability of the progeny and their correction in meiosis

Data supporting the hypothesis about the epigenetic nature of deleterious mutations leading to the death of a part of the progeny are presented. It is assumed that during the life cycle “mutant” variants of formation of structural-functional loop domains occur in chromosomes that normally are corrected during meiosis. An abnormal loop changes the activity of many tens of genes, both increasing (+) and decresing (−) it, which affects the viability of homozygotes and to a lesser extent the viability of heterozygotes. Hybrids with chromosomes containing independently accumulated deleterious mutations partly restore their viability due to the complementary interactions of + and − genes.