Sterility in Crosses of Geographical Races of Drosophila Micromelanica

Abstract

Strains from central Texas and southern Arizona are not distinguishable, but when they are crossed the hybrid [male][male] from Texas [female] X Arizona [male] are sterile; all other F1 hybrids are fully fertile. The sterility is due to the presence of a particular portion of a Texas X chromosome and (probably) Arizona Y. The sterile [male][male] inseminate [female][female] with active sperm, but no larvae develop in eggs laid by these [female][female].