Originally published as Genetics Published Articles Ahead of Print on October 18, 2007.

Genetics, Vol. 177, 2233-2241, December 2007, Copyright © 2007
doi:10.1534/genetics.107.079939

Developmental and Cell Cycle Progression Defects in Drosophila Hybrid Males

Bonnie J. Bolkan^*, Ronald Booker, Michael L. Goldberg^* and Daniel A. Barbash^*,1

^* Department of Molecular Biology and Genetics and Department of Neurobiology and Behavior, Cornell University, Ithaca, New York 14853-2703

¹ Corresponding author: Department of Molecular Biology and Genetics, Biotechnology Bldg., Cornell University, Ithaca, NY 14853-2703.
E-mail: dab87{at}cornell.edu

Matings between D. melanogaster females and males of sibling species in the D. melanogaster complex yield hybrid males that die prior to pupal differentiation. We have reexamined a previous report suggesting that the developmental defects in these lethal hybrid males reflect a failure in cell proliferation that may be the consequence of problems in mitotic chromosome condensation. We also observed a failure in cell proliferation, but find in contrast that the frequencies of mitotic figures and of nuclei staining for the mitotic marker phosphohistone H3 in the brains of hybrid male larvae are extremely low. We also found that very few of these brain cells in male hybrids are in S phase, as determined by BrdU incorporation. These data suggest that cells in hybrid males are arrested in either the G₁ or G₂ phases of the cell cycle. The cells in hybrid male brains appear to be particularly sensitive to environmental stress; our results indicate that certain in vitro incubation conditions induce widespread cellular necrosis in these brains, causing an abnormal nuclear morphology noted by previous investigators. We also document that hybrid larvae develop very slowly, particularly during the second larval instar. Finally, we found that the frequency of mitotic figures in hybrid male larvae mutant for Hybrid male rescue (Hmr) is increased relative to lethal hybrid males, although not to wild-type levels, and that chromosome morphology in Hmr^– hybrid males is also not completely normal.

This article has been cited by other articles:

				S. Aruna, H. A. Flores, and D. A. Barbash Reduced Fertility of Drosophila melanogaster Hybrid male rescue (Hmr) Mutant Females Is Partially Complemented by Hmr Orthologs From Sibling Species Genetics, April 1, 2009; 181(4): 1437 - 1450. [Abstract] [Full Text] [PDF]

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