Gene Transposition as a Cause of Hybrid Sterility in Drosophila

Abstract

We describe reproductive isolation caused by a gene transposition. In certain Drosophila melanogaster – D. simulans hybrids, hybrid male sterility is caused by the lack of a single-copy gene essential for male fertility, JYAlpha . This gene is located on the fourth chromosome of D. melanogaster but on the third chromosome of D. simulans . Genomic and molecular analyses show that JYAlpha transposed to the third chromosome during the evolutionary history of the D. simulans lineage. Because of this transposition, a fraction of hybrids completely lack JYAlpha and are sterile, representing reproductive isolation without sequence evolution.