MILD HEAT-TREATMENT AS AN AGENT OF GENETIC ASSIMILATION IN DROSOPHILA

Population of Drosophila melanogaster adult fertile flies were mantain ed at 31-degrees-C for 120 hours. After this treatment the embryos ori ginated from this population were studied in terms of survival and ter atogenesis. The genetic assimilation character of the observed teratog enic phenotypes was suggested and investigated since at least two kind s alterations resembled phenocopies (of Ebony and Notch), but only phe notye Ebony like was heritable even whithout further treatment of prog eny derived from treated flies. The possible implications at the popul ation level in nature, are discussed taking into account that the magn itude of temperature variation in the experiments (from 26-degrees-C t o 31-degrees-C) is frequently surpassed in the Brazilian Drosophila na tural habitats.