On intra- and interchromosomal associations in Drosophila ananassae

In Drosophila ananassae, three cosmopolitan inversions are very common in natural populations. Chromosomal polymorphism due to these inversions often persists when strains are maintained in the laboratory. A chromosomal analysis of a number of strains was made. Data on the frequencies of different gene sequences will be described separately. During the present investigation the same data have been analyzed in order to test the intra- and interchromosomal interactions in D. ananassae. The results reveal that interchromosomal interactions do not occur with respect to viability as unlinked inversions are associated randomly. However, the linked inversions of the third chromosome show non-random associations maintained by epistatic gene interaction and suppression of crossing over.