The effects of heterozygous inversions on crossing-over in Drosophila ananassae

Abstract

Crossing-over was studied in females of Drosophila ananassae under different karyotypic combinations to detect the effects of heterozygous inversions by utilizing three recessive markers of the second chromosome. Because of the presence of a subterminal inversion (2L) in the heterozygous condition, crossing-over between the cu and b genes is completely eliminated. However, 2L heterozygosity enhances the level of recombination between the b and se genes. Furthermore, two third chromosome inversions when heterozygous also exert an enhancing effect on crossing-over in the second chromosome. These results provide evidence for the existence of intra- and inter-chromosomal effects of inversions on crossing-over in D. ananassae. Key words: Drosophila ananassae, crossing-over, inversions, intrachromosomal effects, interchromosomal effects.