title: Preaching about the converted: how meiotic gene conversion influences genomic diversity.
abstract: Meiotic crossover (CO) recombination involves a reciprocal exchange between homologous chromosomes. COs are often associated with gene conversion at the exchange site where genetic information is unidirectionally transferred from one chromosome to the other. COs and independent assortment of homologous chromosomes contribute significantly to the promotion of genomic diversity. What has not been appreciated is the contribution of another product of meiotic recombination, noncrossovers (NCOs), which result in gene conversion without exchange of flanking markers. Here, we review our comprehensive analysis of recombination at a highly polymorphic mouse hotspot. We found that NCOs make up ∼90% of recombination events. Preferential recombination initiation on one chromosome allowed us to estimate the contribution of CO and NCO gene conversion to transmission distortion, a deviation from Mendelian inheritance in the population. While NCO gene conversion tracts are shorter, and thus have a more punctate effect, their higher frequency translates into an approximately two-fold greater contribution than COs to gene conversion-based allelic shuffling and transmission distortion. We discuss the potential impact of mammalian NCO characteristics on evolution and genomic diversity.
authors.affiliation: Developmental Biology Program, Howard Hughes Medical Institute, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, New York, USA. ColeF@mskcc.org
authors.forename: Francesca
authors.initials: F
authors.lastname: Cole
authors.forename: Scott
authors.initials: S
authors.lastname: Keeney
authors.forename: Maria
authors.initials: M
authors.lastname: Jasin
mesh_terms: D000483:Alleles; D000818:Animals; D003434:Crossing Over, Genetic; D005785:Gene Conversion; D014644:Genetic Variation; D015894:Genome, Human; D006801:Humans; D008540:Meiosis; D017422:Sequence Analysis, DNA