Gametic incompatibilities between races of Drosophila melanogaster

• Published in: Proceedings of the Royal Society. B, Biological sciences Vol. 268; no. 1469; pp. 789 - 795
• Main Authors: Alipaz, J. A., Wu, C., Karr, T. L.
• Format: Journal Article
• Language: English
• Published: England The Royal Society 22-04-2001
• Subjects: Animals; Crosses, Genetic; Data lines; Drosophila; Drosophila melanogaster; Drosophila melanogaster - genetics; Drosophila melanogaster - physiology; Evolutionary genetics; Female; Female animals; Fertilization; Fertilization - genetics; Gametic Incompatibility; Incipient Speciation; Male; Male animals; Mating behavior; Ova; Reproduction - genetics; Reproductive Isolation; Species Specificity; Spermatozoa; Viability
• ISSN: 0962-8452; 1471-2954
• DOI: 10.1098/rspb.2000.1420

Reproductive-isolating mechanisms between nascent species may involve sperm-egg recognition and have been best described in externally fertilizing organisms where such recognition is essential in preventing undesirable fertilizations. However, reproductive barriers in internally fertilizing species differ in significant ways, and a direct role for sperm-egg interactions has yet to be demonstrated. Females of many strains of Drosophila melanogaster from Zimbabwe, Africa, do not mate readily with cosmopolitan males. This polymorphism in mate choice is postulated to represent incipient speciation. We now report that, in one direction, crosses between the above populations produce far fewer offspring than reciprocal crosses due to a lower rate of egg hatch. We established that egg inviability in these crosses was due to defects in fertilization. Thus, even in taxa with internal fertilization, gametic incompatibility may be a mechanism relevant to reproductive isolation during incipient speciation.