CHROMOSOME STUDIES IN WILD POPULATIONS OF D. MELANOGASTER

Harrison D. Stalker ¹

¹ Department of Biology, Washington University, St. Louis, Missouri 63130

Chromosome studies of wild D. melanogaster populations from Missouri, Mississippi, Louisiana and Texas uncovered 58 inversions. Six were common and cosmopolitan; 52 were new, rare and generally endemic. In one of two Missouri populations tested, structurally heterozygous females carried significantly more sperm at capture than did the homozygotes. In both populations comparisons of wild sperms with the females carrying them indicated significant positive assortative mating and an excess production of homozygotes among the F₁ progeny. Wild females structurally heterozygous in up to three major autosomal arms showed no associated nondisjunctional egg lethality; those heterozygous in all four arms produced from 0% to 24% dead eggs, suggesting the presence of intrapopulational gene modifiers of meiosis. Texas populations supported on windfall citrus fruit showed a slight but significant difference in inversion frequencies between flies breeding on oranges and those breeding on grapefruit. Within these populations inversions were not distributed at random among individuals; rather there was an observed excess of individuals carrying intermediate numbers, and a deficiency of those carrying very few or very many inversions. While there was no significant linkage disequilibrium associated with this central tendency, there was a significant interchromosomal interaction: flies carrying inversions in chromosome 2 tended not to carry them in chromosome 3, and vice versa.

This article has been cited by other articles:

				T. L. Turner, M. T. Levine, M. L. Eckert, and D. J. Begun Genomic Analysis of Adaptive Differentiation in Drosophila melanogaster Genetics, May 1, 2008; 179(1): 455 - 473. [Abstract] [Full Text] [PDF]

				M. T. Levine and D. J. Begun Evidence of Spatially Varying Selection Acting on Four Chromatin-Remodeling Loci in Drosophila melanogaster Genetics, May 1, 2008; 179(1): 475 - 485. [Abstract] [Full Text] [PDF]

				W. J. Kennington, L. Partridge, and A. A. Hoffmann Patterns of Diversity and Linkage Disequilibrium Within the Cosmopolitan Inversion In(3R)Payne in Drosophila melanogaster Are Indicative of Coadaptation Genetics, March 1, 2006; 172(3): 1655 - 1663. [Abstract] [Full Text] [PDF]

				S. Kusakabe, Y. Yamaguchi, H. Baba, and T. Mukai The Genetic Structure of the Raleigh Natural Population of Drosophila melanogaster Revisited Genetics, February 1, 2000; 154(2): 679 - 685. [Abstract] [Full Text]

				A. S. Gilchrist and L. Partridge A Comparison of the Genetic Basis of Wing Size Divergence in Three Parallel Body Size Clines of Drosophila melanogaster Genetics, December 1, 1999; 153(4): 1775 - 1787. [Abstract] [Full Text]