[Deleterious mutations in various Drosophila melanogaster strains carrying meiotic mutation c(3)G]

In the absence of meiotic recombination, deleterious mutations, decreasing the viability, are accumulated and fixed in small Drosophila populations. Study of the viability of hybrid progenies of three laboratory Drosophila melanogaster strains carrying meiotic mutation c(3)G17 has suggested that the deleterious mutations are negatively synergistic in their interaction. The deleterious mutations localized to the pericentromeric region of chromosome 3 are threefold more efficient as compared with the mutations located in distal regions. Substitution of a new chromosome for the balancer chromosome in a strain with meiotic mutation c(3)G17 partially restores (by approximately 20%) the viability of homozygotes c(3)G17/c(3)G17 over the first 20-30 generations. Further cultivation for 30 generations with the same balancer again decreases the viability to the initial level. An epigenetic nature of deleterious mutations is discussed.