Chadov, B.F., Chadova, E.V., Kopyl, S.A., Anan'ina, G.N. (1999). [Chromosome rearrangement: two ways of influencing crossing over in Drosophila.]  Genetika, Moscow 35(4): 459--466.

FBrf0109477

Research paper

Insertion of the Y-material into the 34A Is(Y;2L)419 region diminished recombinational length of the left arm of chromosome 2 (2L) from 49.1 to 15.0 cM. This decrease was compensated by the increase of recombinational length in the other chromosomal arms due to interchromosomal effect. The increase in the X chromosome was 11.4 cM; it was 2.0 cM in chromosome 2R; and 17.3 cM in chromosome 3. The insertion-induced decrease of the 2L recombinational length could be eliminated by evoking interchromosomal effects from other chromosomes. The presence of the inversion in the X chromosome increased the 2L recombinational length from 15.0 to 30.2 cM, while its association with the In(3LR)D inversion increased this length to 45.6 cM. The interchromosomal effects in the inductor chromosome were induced by distortion of pairing rather than by the low recombinational length of this chromosome. For example, the interchromosomal effect of the insertion on the X chromosome was higher in the Is(Y;2L)/+; In(3LR)/+ females than in the Is(Y;2L)/+; +/+ females (15.4 versus 11.5 cM), though the 2L recombinational length in the females with the former genotype (30.2 cM) was twofold higher than in females with the latter genotype (15.0 cM). It is suggested that chromosomal rearrangement hampers the development of local contacts in the homologues. This delay affects crossing over in the given pair of homologues in two ways: directly via diminishing the number of exchange sites, and indirectly through regulatory delay of crossing over determination in the meiocyte. The effects of the insertion on crossing over in nonhomologous chromosomes are implemented by through the second way.