The landscape of recombination in African Americans

Abstract

Recombination, together with mutation, is the ultimate source of genetic variation in populations. We leverage the recent mixture of people of African and European ancestry in the Americas to build a genetic map measuring the probability of crossing-over at each position in the genome, based on about 2.1 million crossovers in 30,000 unrelated African Americans. At intervals of more than three megabases it is nearly identical to a map built in Europeans. At finer scales it differs significantly, and we identify about 2,500 recombination hotspots that are active in people of West African ancestry but nearly inactive in Europeans. The probability of a crossover at these hotspots is almost fully controlled by the alleles an individual carries at PRDM9 (P<10−245). We identify a 17 base pair DNA sequence motif that is enriched in these hotspots, and is an excellent match to the predicted binding target of African-enriched alleles of PRDM9.

Population Genetics in the Genomic Era

“…And individuals who carry the motif tend to have a higher risk of the disease-causing genomic rearrangements. Wegmann et al [30] showed that recombination rates at regions with known large chromosomal structural variants, especially inversions, are likely to be highly population specific compared with those at other regions.…”

“…Based on the observed ancestry switch points in admixed population, Hinch et al [29] and Wegmann et al [30] constructed a high-resolution recombination map of African American in 2000, respectively. It was novel to use ancestry-based approach to identify recombination events and recombination hotspots.…”

Models, methods and tools for ancestry inference and admixture analysis

“…A miscopy rate parameter is used to account for the differences between "real" and "copied" ancestry. In HAPMIX, an EM algorithm is used to estimate those parameters for African Americans [109].…”

Editorial: Genetics of Barrett's: The Bigger, the Better

“…However, the study presented here remains relatively small when one looks at the individual disease groups (200 + for each of refl ux cases, Barrett ' s and EAC). Specifi cally, the variation of genetic material between worldwide human populations is 0.1 % of the genome ( 14 ). Since BE is more common in white males especially in Caucasians, the need for well-characterized ethnic and gender controls such as provided here is vital to avoid potentially spurious diff erences as could be present here.…”