DNA crosslink repair safeguards genomic stability during pre-meiotic germ cell development

Germline de novo mutations are the basis of evolutionary diversity but also of genetic disease. However, the molecular origin, mechanisms and timing of germline mutagenesis are not fully understood. Here, we define a fundamental role for DNA interstrand crosslink repair in the germline. This repair process is essential for primordial germ cell (PGC) maturation during embryonic development. Inactivation of crosslink repair leads to genetic instability that is restricted to PGCs within the genital ridge during a narrow temporal window. Having successfully activated the PGC transcriptional program, a potent quality control mechanism detects and drives damaged PGCs into apoptosis. These findings therefore define a source of DNA damage and the nature of the subsequent DNA repair response in germ cells, which ensures faithful transmission of the genome between generations.