Aberrant Forms in Drosophila and Sex Differentiation

Abstract

By the means of x-rays the X-chromosome of D. melanogaster was fragmented into several pieces, and these f fragments were tested separately for the presence of a possible major sex factor. All regions of the X were tested by this method. Such a factor was not found in any of the regions excepting in a very small section, consisting of 4 bands and located in the middle region of the chromosome. Every effort to secure [male][male] hyperploid for this small section has failed; apparently such flies are completely in-viable. The failure of these flies to survive may lead some to assume that the small fragment may contain the postu-lated major sex factor, but such evidence is negative and not critical.