Accumulation of deleterious genes in a cage population of Drosophila melanogaster.
Lethal and sterility mutations were accumulated in a cage population which was initiated with lethal- and sterility-free second chromosomes of D. melanogaster. It took about 2,000 days for the frequencies of these genes to reach equilibrium levels, i.e., 18% lethal and 9% male-sterile chromosomes. Two other cage populations which were initiated with random chromosomes sampled from natural populations and kept for more than eleven years in the laboratory showed 19-20% lethal content. The elimination rates of lethals by homozygosis in these populations were smaller than the mutation rate. By using NEI's formulae, the deleterious effect of a lethal gene in heterozygous condition (h) was estimated to be 0.035. The effective population number in the cage populations was estimated to be 1,000-2,900, while the actual population number was 3,500-7,800.
D000483:Alleles; D000818:Animals; D004331:Drosophila melanogaster; D005260:Female; D005787:Gene Frequency; D005804:Genes, Lethal; D005828:Genetics, Population; D006720:Homozygote; D007246:Infertility / Q000235:genetics; D008297:Male; D009154:Mutation; D011336:Probability; D013997:Time Factors