The Role of Heterochromatin in Karyotype Variation Among Hawaiian Picture-Winged Drosophila

Abstract

A comparison is made of the amount and distribution of heterochromatin in the mitotic chromosomes of species of the Hawaiian picture-winged Drosophila, and metaphase configurations among these species are compared with those from other regions. Of 103 picture-winged species, only three species (D . melanocephala, D. cyrtoloma, and D. prostopalpis) have any metacentric or submetacentric chromosomes, and only six species have a haploid complement of six acrocentric chromosomes rather than the "primitive" karyotype of five rods and a microchromosome. All karyotype modifications among the picture-winged species can be explained on the basis of modifications in the amount and distribution of heterochromatin; there is no evidence of pericentric inversions or chromosomal fusion.