Enhancer and suppressor system of male recombination in Drosophila ananassae.

Abstract

Genetic elements controlling male recombination were detected in the autosomes of the two wild strains, L8 and TNG, and a marker stock, b Arc se; bri ru, of Drosophila ananassae.In the L8 strain, a dominant enhancer, En (2) -cm, which acts on both chromosomes 2 and 3 in unison, is located between the b and Arc loci in the left arm of chromosome 2. In addition, a reducer, Ra, of the En(2)-cm is located in the right arm of chromosome 3 of this strain.The action of the reducer is expressed as progressive decrease in recombination frequency with increasing age of male parent.No such single major enhancer was present in the TNG strain. However, each of the three arms, 2L, 2R, and 3R, was found to carry genetic elements which cause male recombination.A suppressor, Su (2) -bs, which almost completely suppresses male recombination in males carrying En (2) -cm, was found in the left arm of chromosome 2, between the bw and Arc loci, of the b Arc se; bri ru stock. This suppressor has no effect on the polygenic enhancers of the TNG strain.

Positive correlation between male recombination and Minute mutation frequencies in Drosophila ananassae.

“…DISCUSSION Hinton (1970Hinton ( , 1974 identified an enhancer-suppressor system of male crossing-over in D. ananassae, in which a dominant enhancer in chromosome 3 is suppressed by either a chromosome 2 linked suppressor or an extrachromosomal suppressor. Lately, Matsuda and Tobari (1983) suppressor system of male crossing-over; an enhancer in the left arm of chromosome 2 of the L8 strain and a suppressor against the L8 enhancer in the left arm of chromosome 2 of the b Arc se; b ri ru stock. In addition, a polygenic enhancer system in the TNG strain, which is free from the effect of the suppressor, has also been identified.…”

“…Moriwaki and Tobari 1975). Diverse genetic systems controlling mutation (Hinton 1979(Hinton , 1981 and male recombination (Hinton 1970;Moriwaki et al 1970;Moriwaki et al 1979;Matsuda and Tobari 1983) have been demonstrated.…”

Discriminative effects of male age on male recombination and Minute mutation frequencies in Drosophila ananassae.

“…This indicates that there exists a factor (or factors) in L8 which is responsible for changing the frequencies of male recombination, and which acts on chromosomes 2 and 3 in common or, more probably, throughout the genome. Indeed, we have located in the L8 strain an enhancer of male recombination on chromosome 2 and a factor (reducer) on chromosome 3 which modifies the effect of the enhancer, according to the age of the male (Matsuda and Tobari 1983).…”

“…In D, ananassae, the ageing effect on male recombination has also been demonstrated only in a particular cross (Matsuda and Tobari 1982 and the present report). In this particular cross, analyses have resulted inrecognition of the enhancer of male recombination and the modifier of the enhancer (Matsuda and Tobari 1983), which is a different genetic system from the P-M one.…”

Male recombination in Brazilian populations ofDrosophila ananassae

“…ananassae is controlled by chromosomal dominant enhancer genes, En(s) in chromosome 3 and En-II in chromosome 2. Since then, genetic elements controlling male crossing over have been mapped on chromosomes 2 and 3 (Hinton 1970;Matsuda and Tobari 1983). In all these studies, male crossing over was demonstrated using F 1 individuals from crosses between wild type strains and marker stocks.…”