CYTOLOGICAL AND PHYLOGENETIC RELATIONSHIPS IN THE REPLETA GROUP OF THE GENUS DROSOPHILA

Abstract

Cytotaxonomic studies in the repleta group have demonstrated phylogenetic relationships among 46 species, most of which are cyto-logically unique although there has been a minimal amount of in-versional evolution. It is proposed that the primary selective advantage of an inversion is to allow for the development of coadapted gene complexes specialized for the particular environment; thus the geographical distribution and species distribution is the result of selective rather than random processes. The role of allopatric cytological differentiation in speciation is discussed as is speciation in the mulleri complex.