Anjali Gupta Hinch

Abstract Over the past decade, genomic modelling has revealed a rich tapestry of admixtures shaping present-day human populations. These have largely focused on the past few thousand years, when ancestral populations are either well characterised by present-day genomic diversity or directly observed through ancient DNA. Genomic modelling and fossil evidence have so far only provided a fragmented picture of the coexistence and mixing of human groups in the deeper past.

Highlights • DMC1 binds near and RAD51 away from DNA break sites on homology search filaments • RPA binds the repair template chromosome in mammalian meiotic D-loops in vivo • DMC1, not RAD51, performs strand exchange in mammalian meiotic DNA break repair • D-loops resemble crossover gene conversion tracts in size and localization Summary Meiotic recombination proceeds via binding of RPA, RAD51, and DMC1 to single-stranded DNA (ssDNA) substrates created after formation of programmed DNA...

Sequencing and the single sperm During meiosis, homologous chromosomes undergo doublestrand breaks in DNA that can cross over, shuffling genetic material. However, not every double-strand break resolves in a crossover event. Hinch et al. wanted to determine the rules governing DNA recombination. They developed a method to sequence individual mouse sperm and applied it to mice carrying two different alleles of a protein involved in mammalian crossovers.