Tumori in Diverse Specie Del Genere Drosophila

Abstract

Melanotic bodies, in all similar to the tumors described in Drosophila melanogaster, were found in natural populations of the following species of the genus Drosophila: D. campestris, D. bainderantorum, D. bocainensis. D. griseolineata, D. guaramunú, D. immigrans, D. mediostriata, D. mediopunctata, D. nebulosa, D. repleta, D. simulans, D. sturtevanti, D. virilis, D. willstoni. In stocks maintained in the laboratory for a long time, it was determined that the frequency of tumors varied from 0 to 5‰, with a mean value of 1-2‰. The highest percentage was found in the D. sturtevanti - Belem strain (2.08%). Different strains from a same species had different tumor frequencies. The study of the offspring of tumor bearing flies, and the cross of strains selected for a high frequency of tumors, reveled that these were inherited through rcessive genes of incomplete penetrance. As in D. melanogaster, the tumors appear in the larval stage and regress at the end of this period loading themeselves with melanic pigments. These melanized tumor rests persist in the pupae and adults’ as foreing bodies which apparently produce no important alterations to their bearers.