Common long human inversion polymorphism on chromosome 8p

In an analysis of human crossover interference, we identified apparent triple recombination events, in a short region on chromosome 8p, on the maternallyderived chromosomes in four individuals (two from each of two families). While this may have indicated an error in marker order, the inverted order was inconsistent with recombination events in other individuals. We were thus led to the hypothesis of an inversion polymorphism in the region, which was subsequently confirmed by fluorescent in situ hybridization (FISH). The inversion spans approximately 12 cM on the female genetic map and 2.5 – 5.3 Mb on the physical map. The allele frequency of the inverted order (D8S1130 telomeric; D8S351 centromeric) in 50 individuals of European ancestry was 21%. This is only the second known common, long inversion polymorphism in the human genome.