<i>Drosophila</i> Hybrids in Nature: Proof of Gene Exchange Between Sympatric Species

Abstract

Genetic studies of two closely related endemic Hawaiian species show that in one area of sympatry about 2 percent of the naturally occurring individuals are hybrids. More than 20 times this many would be expected if the population consisted of a single panmictic unit. Despite hybridization, natural selection appears to maintain the essential integrity of each separate gene pool.