Male recombination in Brazilian populations ofDrosophila ananassae

Abstract

With few exceptions, spontaneous crossing over does not normally occur in male Drosophila. Drosophila ananassae males show considerable amounts of crossing over. In wild males of D. ananassae from Asian (2008) and Brazilian populations (1986 and 2007) variable frequencies of meiotic crossing over, estimated from chiasmata counts, suggested the existence of factors controlling male crossing over in these populations. To corroborate for such prediction, we present data on spontaneous recombination in F1 males of D. ananassae heterozygous for chromosomes of the same Brazilian populations (1986) and marker chromosomes using three testers stocks. Mean recombination value was low, although high variability existed between individual frequencies. Recombination frequencies between lines in each tester stock were not significantly different, excepting when the 3ple-px and 3ple-cy testers were compared (p < 0.05). These two testers differ in respect to the regional distribution of crossovers. The occurrence of recombination in chromosomes 2 and 3 in F1 males tested with e(65) se; bri ru was not related, suggesting they are under independent genetic control. Our data are consistent with proposed genetic factors controlling male crossing over in the tester stocks and to the presence of enhancers and suppressors of male crossing over segregating in the Brazilian populations (1986).

To Break or Not To Break: Sex Chromosome Hemizygosity During Meiosis in Caenorhabditis

“…Ultimately, DSBs will need to be mapped at the molecular level to determine what chromosomal features facilitate DSB formation in Caenorhabditis, and whether this is altered between species. There is precedence for differences in recombination between species in the same genus as illustrated in Drosophila where D. melanogaster males do not exhibit any meiotic recombination, while some populations of D. ananassae do (Goni et al 2016). Further, recombination can vary widely between the sexes, and even within individuals of the same species (Fledel-Alon et al 2011).…”