Effects of the parents' age on the level of polymorphism at the Adh locus in Drosophila melanogaster: I. Effects on the genic and genotypic segregation of the offspring.

Several parameters (genetic and nongenetic) are involved in allele frequency changes and in the maintenance of the level of polymorphism at the Adh locus in Drosophila melanogaster. In this article, we have investigated the effect that parental age has on the genetic and genotypic segregation of the offspring. Comparing the offspring from crosses between heterozygous individuals of different ages (young x young, young x old, and old x old), we observed an association between adult age and allele frequencies of the offspring. The offspring of the "older" parents have a greater frequency of the Adh-F allele compared to the offspring of "younger" parents. However, this effect is not independent of the sex of parents. The age of the male has more importance than the female age. Furthermore, the duration of the parent egg-laying period also affects the genic frequencies among the offspring. The frequency of the F allele, in each cross, gradually decreases while the egg-laying period increases.