In Science this week, University of Oxford scientists describe the whole-genome sequencing of single sperm cells, uncovering the factors that influence meiotic recombination. The team sequenced 217 individual hybrid mouse sperm, generating a kilobase-resolution genome-wide map of crossovers. By combining this map with molecular assays measuring stages of recombination, they identify factors that affect crossover probability including PRDM9, a protein involved in positioning recombination hotspots during meiosis. The factors the scientists identify also prove to influence the time for sites of recombination-initiating DNA double-strand breaks to find and engage their homologs, and they further show that chromatin environment on the template homolog affects positioning of crossover breakpoints. "Our results also offer insights into recombination in the pseudoautosomal region," the authors write. GenomeWeb has more on this, here.
And in Science Translational Medicine, an international team report the identification of a genetic alteration in malaria-transmitting mosquitos that provides the insects with resistance to a widely used class of insecticides called pyrethroids. The researchers combined different sequencing techniques to analyze the major African malaria vector Anopheles funestus, finding a single cytochrome allele in the gene CYP6P9a promotes resistance to pyrethroids. Using a novel DNA-based assay, the investigators further show that the allele is common to A. funestus in southern Africa, but not elsewhere on the continent. A field study, meanwhile, shows that mosquitos carrying the allele could more effectively feed on human volunteers who slept in huts with pyrethroid-coated bednets. "Our findings highlight the need to introduce a new generation of insecticide-treated bednets for malaria control that do not rely on pyrethroid insecticides," they write.