Abstract
Although the past decade has seen tremendous progress in our understanding of fine-scale recombination, little is known about non-crossover (or “gene conversion”) resolutions. We report the first genome-wide study of non-crossover gene conversion events in humans. Using SNP array data from 94 meioses, we identified 107 sites affected by non-crossover events, of which 51/53 were confirmed in sequence data. Our results suggest that a site is involved in a non-crossover event at a rate of 6.7×10−6/bp/generation, consistent with results from sperm-typing studies. Observed non-crossover events show strong allelic bias, with 70% (61–79%) of events transmitting GC alleles (P=7.9×10−5), and have tracts lengths that vary over more than an order of magnitude. Strikingly, in 4 of 15 regions with available resequencing data, multiple (∼2–4) distinct non-crossover events cluster within ∼20–30 kb. This pattern has not been reported previously in mammals and is inconsistent with canonical models of double strand break repair.
