[Genetic control of isolating mechanisms in the genus Drosophila]

Published data on the genetic control of isolating mechanisms in the genus Drosophila are discussed. The main isolation types of genetic mechanisms (ecological isolation, behavioral isolation, hybrid sterility, and the inviability or impaired development of interspecific hybrids) are considered. It is shown that each of the isolation barriers between different species is controlled by a small number of genes. However, as each pair of sibling species is usually separated by several barriers, the total number of isolation genes is about 20 to 30. The probable sequence of events in the appearance of isolation barriers during the divergence of novel species is discussed. A concept of the consolidation of a new species is proposed. This concept is based on the assumption of the genetic determination of behavior that promotes crossing between individuals of the new genotype and constrains their crosses with individuals of the ancestral genotype.