Functional and evolutionary impact of polymorphic inversions in the human genome

Inversions are one type of structural variants linked to phenotypic differences and adaptation in multiple organisms. However, there is still very little information about inversions in the human genome due to the difficulty of their detection. Here, thanks to the development of a new high-throughput genotyping method, we have performed a complete study of a representative set of 45 common human polymorphic inversions. Most inversions promoted by homologous recombination occur recurrently both in humans and great apes and, since they are not tagged by SNPs, they are missed by genome-wide association studies. Furthermore, there is an enrichment of inversions showing signatures of positive or balancing selection, diverse functional effects, such as gene disruption and gene-expression changes, or association with phenotypic traits. Therefore, our results indicate that the genome is more dynamic than previously thought and that human inversions have important functional and evolutionary consequences, making possible to determine for the first time their contribution to complex traits.