X-ray induced mutations causing adult life-shorting in Drosophila melanogaster

Abstract

The genetic control of adult life span has been studied in the fruit fly, Drosophila melanogaster, by investigating mutations which markedly decrease, longevity. Three such adult lethal mutations (AL1, AL2 and AL3) were produced by X-radiation of males. Their mean adult life spans were 35, 13 and 29 days, respectively, as opposed to 69 days for the unirradiated controls. Females, also, exhibit life-shortening when they are homozygous for any of the 3 mutations. Their mean adult life spans were 30, 15 and 24 days, respectively, whereas that of unirradiated control females was 62 days. Survivorship curves were characteristic for each mutant, with the effective lethal phase occurring at a different period in the adult life of each one. From these curves it was deduced that the mode of action of AL2 and AL3 may be similar, but that AL1 acts in a different way. None of the 3 adult lethal mutations was an allele of another, as shown by the mean adult life span of females heterozygous for any combination of the 3. When the unirradiated wild type strain was screened for the presence of adult lethal mutations none was found in the sample tested to date. The implications of adult lethal mutations for the study of aging and development are discussed.