Supergene

A supergene is a chromosomal region encompassing multiple neighboring genes that are inherited together because of close genetic linkage, i.e. much less recombination than would normally be expected.The earliest use of the term "supergene" may be in an article by A. Ernst (1936) in the journal Archiv der Julius Klaus-Stiftung für Vererbungsforschung, Sozialanthropologie und Rassenhygiene.[6] Classically, supergenes were hypothesized to have evolved from less tightly-linked genes coming together via chromosomal rearrangement or reduced crossing over, due to selection for particular multilocus phenotypes.For instance, in Batesian mimicry supergenes in species such as Papilio memnon, genes are required to affect hind-wing, fore-wing, and body colour, and also the presence or absence of long projections (the "tails" of swallowtail butterflies).Analysis of Nabour's data by Darlington & Mather concluded that the genes responsible for the morphs of Paratettix texanus have been gradually aggregated into a group which acts as a single switch-mechanism.That crossing-over can be suppressed by selection has been known for many years; Detlefsen and Roberts were able to reduce recombination between the loci for white eyes (w) and miniature wings (m) in Drosophila melanogaster from the normal 36% to 6% in one line and 0.6% in another.