Meiotic DNA breaks drive multifaceted mutagenesis in the human germline

Post seminar tea, coffee and biscuits will be available in the Combination Room.

Meiotic recombination commences with hundreds of programmed DNA breaks, however the degree to which they are accurately repaired remains poorly understood. We report that meiotic recombination is 8-fold more mutagenic for single-base substitutions than was previously understood, leading to de novo mutation in 1 in 4 human sperm and 1 in 12 human eggs. Its impact on indels and structural variants is even higher, with 100-1400-fold increases in rates per break. We uncover novel mutational signatures and footprints relative to break sites, which implicate error-prone mechanisms including translesion synthesis and end-joining repair pathways in meiotic break repair. These mechanisms drive mutagenesis in human germlines and lead to disruption of hundreds of genes genome-wide.