A COMPARATIVE STUDY OF INDUCED INCREASES IN PROXIMAL RECOMBINATION INDROSOPHILA MELANOGASTERFEMALES

Abstract
Crossing over was studied in females between f - car - bb1 -Dp(y+) on the X chromosome. Mitomycin C and [gamma]-rays increased crossing over in all 3 regions, increased nondisjunction and affected meiotic as well as gonial cells. Temperature was recombinagenic only in the car - bb1 region and the autosomal inversions, Cy and Ubxl30 increased crossing over in both regions containing euchromatin (f -car and car - bbl). Actinomycin D-treatment resulted in a slight decrease in crossing over. The data indicate that there may be 2 general classes of recombinagens, those that affect crossing over in proximal euchromatin and those which, in addition, induce breaks in heterochromatin.