Hundred Years of Research on Inversion Polymorphism in Drosophila

Paracentric inversions are widespread in the genus Drosophila. Naturally occurring chromosome inversions were detected very early indirectly as far as genetics history is concerned. Sturtevant in 1917 found that in certain strains of D. melanogaster reduced recombination was due to inversions in order of genes in chromosomes, a proposal which was subsequently verified by him in 1926 and 1931 based on the data of genetic mapping. The physical reality of chromosomal inversions was confirmed with the discovery of giant salivary gland chromosomes in Drosophila by Painter in 1933. From which the gene order could be known from the banding pattern. Since the initial work of Sturtevant in 1917 on inversions in Drosophila, hundred years have lapsed and chromosomal polymorphism due to inversions in a large number of species of the genus Drosophila has been extensively studied by using polytene chromosome maps. About one hundred species of Drosophila have been found to be chromosomally polymorphic. Hundred years of research on inversion polymorphism in Drosophila have revealed that inversions in Drosophila are important from view point of population and evolutionary studies. This review briefly summarizes the important findings pertaining to the research of hundred years on inversion polymorphism in different species of Drosophila.