INTERCHROMOSOMAL EFFECTS ON CROSSING OVER INDROSOPHILA MELANOGASTER. IV. ALL COMPOUND X CHROMOSOMES

Abstract

AU 6 compound X chromosomes were tested for their effects on crossing over in chromosome 3 between Ly-st-pp-Sb. Crossover values in females carrying the reversed metacentric were used as controls. Crossing over was increased by all compounds Xs, the st-pP region having the largest relative increase. The reversed acrocentric was most recombinagenic and the reversed compound ring, the least. The addition of a Y chromosome tended to decrease these effects. These data extend the observation that all chromosomes which synapse as rings or loops increase crossing over in other chromosomes.