THE OCCURRENCE OF PARTIALLY FERTILE TRIPLOID METAFEMALES IN DROSOPHILA MELANOGASTER

Abstract

Genetic and cytological proof is given for the occurrence of triploid metafemales contai ling 4 chromosomes I, 3 chromosomes II, 3 chromosomes III, and 2 chromosomes IV. Phenotypically the triploid metafemales resemble triploid females in their large eye facets, stout bristles and caorse wings, and resemble diploid metafemales in their rough eyes and narrow wings with cut and excised inner margins. Viability of triploid metafemales is much higher than that of diploid metafemales and they are also partially fertile. Five of the 49 triploid metafemales collected were fertile, these 5 producing a total of 48 offspring. The partial fertility of triploid metafemales yielded data on chromosome segregation and crossing over frequency.