eLife assessment:
This fundamental study provides compelling evidence that long-range resection is important for recombination between distal, but not proximal, homologous sequences. It is thus proposed that a major role of long resection of a double-strand break mediated by Sgs1 and Exo1 is to activate the DNA damage checkpoint to allow the chromosomal mobility needed for the DNA ends to find a distant homologous sequence with which repair via homologous recombination, adding a new biological meaning to the role of long DNA resection in homologous recombination.