The nature and number of genetic changes required to form two new species from one ancestral one is a lingering problem in evolutionary biology. A defining feature separate species is their inability to form fertile hybrids. A pair of Drosophila species between which a low number of fertile hybrids still form, have been discovered. By using this pair of species, D. mojavensis and D. arizonae, a combination of molecular and classical genetic techniques can be used to determine how many genetic factors are responsible for the emerging sterility and the chromosomal locations of the factors. Anthropogenic change is fueling the loss of species at an alarming rate. While we have some understanding of the factors that cause loss of species, our understanding of how new species form is sorely lacking. The present study will provide important new information about the origin of new species. At the same time, it will advance our understanding of the genetics of sterility of male insects. Sterile male insect techniques are an important tool in the control of economically important insect pests.
