Cytogenetic analysis of recombination in males of Drosophila ananassae.

Cytogenetic studies of recombination in males of Drosophila ananassae were carried out by examining F1 males derived from he mating of marker females, b se; bri ru of the BS stock, with males of two wild strans, TNG and L8. The male recombination values in both sections b-se (chromosome 2) and bri-ru (chromosome 3) are high in TNG F1 but extremely low in L8 F1. We demonstrate the presence of chiasmata in TNG F1 males at a frequency capable of accounting for the observed recombination values. A unique series of "iso-site aberrations" was also observed in TNG F1 males. Because of a parallelism in the distribution pattern between the chiasmata and the iso-site aberrations, we propose that recombination in males of D. ananassae is meiotic in origin and that the iso-site aberrations are related to chiasma formation.