Protein Differences in Drosophila. IV. A Study of Sibling Species

Nine triads of species of the genus Drosophila, each triad composed of a pair of sibling species and a form closely related but morphologically distinct, were studied using electrophoretic techniques at an average of 18 loci per species. The sibling pairs, on the average, shared proteins with identical mobility 50% of the time, while a sibling and a morphologically distinct form shared proteins with identical mobility only 18% of the time. One sibling pair shared proteins with identical mobility 85% of the time. These findings are discussed with special reference to "the reorganization of the gene pool" during speciation.