GYNANDROMORPHISM IN ANOSTRACA - MULTIPLE MECHANISMS OF ORIGIN

Gynandromorphism is relatively rare in anostracans and is generally th ought to arise from mitotic aberrations occurring during early embryog enesis that create somatic-cell mosaics. We have reared 35 gynandromor phic Branchinecta, most of them being B. lindahli. The morphology of t hese individuals, the relatively high frequency of their occurrence, a nd their aggregation within sibships but not within pedigrees, indicat e that they are not the result of mutational events. Their differentia l appearance in female-biased sibships suggests, instead, that the maj ority of them represent males that have been incompletely transformed into females by epigenetic feminizing factors.