Rôle of the Autosomes in the Drosophila Pseudoobscura Hybrids

Abstract

F1 hybrid oo between A and B races are fertile, and can be back-crossed to [male][male] of the parental races. Non-disjunction of the X-chromosomes takes place in the gametogenesis in such [female][female]. XO [male][male] are produced that have the X-chromo-some from their father, cytoplasm from their mother and grandmother, and a varying number of autosomes of both races. These XO [male][male] are variable in respect to testis size, and course of spermatogenesis (including chromosome pairing). It is concluded that autosomes are concerned with the sterility of the interracial hybrids in this species.