[Mutagenesis and interchromosomal effect on crossing over in Drosophila].

The possibility of mutational consequences of interchromosomal effect on crossing-over was studied in Drosophila melanogaster females with four genotypes: (1) structurally normal (control); (2) heterozygous at In(1)-Muller-5 inversion (X chromosome); (3) heterozygous at In(3LR)CxD inversion (chromosome 3); and (4) heterozygous at both inversions. The mutational effect was determined through the loss of autosome 2 and formation of arm compounds C(2L) and C(2R). In females with recombinations, the rate of mutational events did not exceed that of the control. It was concluded that interchromosomal effect on crossing-over is of a regulatory character and disturbs neither recombination itself nor chromosome pairing. Coorientation X-3 leading to the appearance of intersexes in the progeny occurred in meiosis in females with two inversions.