Recombination initiation maps of individual human genomes. Homo sapiens

DNA double-strand breaks (DSBs) are introduced in meiosis to initiate recombination and to generate crossovers, the reciprocal exchanges of genetic material between parental chromosomes. Here we present the first high-resolution map of meiotic DSBs in individual human genomes. Comparing DSB maps between individuals shows that along with DNA binding by PRDM9, additional factors dictate the efficiency of DSB formation. Furthermore, we find that in human males, the frequency of DSB formation is the primary determinant of crossover rate. Patterns of sequence polymorphisms around meiotic DSB hotspots provide evidence for both GC-biased gene conversion and for a mutagenic role of DSB repair and/or recombination. Finally, we provide compelling evidence that the aberrant repair of meiotic DSBs is a driver of human genomic disorders. Overall design: Detection of meiotic double strand breaks in testis of several human male individuals.