Inversions and Evolution of the Human Genome

Inversions are a type of naturally occurring DNA mutation in which the sequence of the DNA is reversed, resulting in it being read in the opposite direction to the wild type. Most of these inversion mutations are thought to have no direct phenotypic effect, although those that do are often lethal. Although inversions are mostly phenotypically functionless, inversions cause recombination suppression both within and extending slightly outwards from the inverted region. Recombination suppression between heterozygotic inversions can lead to linkage disequilibrium and cause the independent evolution of chromosomes, eventually leading to speciation. Comparative genomics of humans and primates has identified many inversions which may have contributed to the evolution of the human genome. Population genomics has also identified many inversions which are polymorphic in humans, some of these are under selection and may be contributing to the continued evolution of the human genome.