THE METAPHASE AND POLYTENE CHROMOSOMES OF DROSOPHILA SERIEMA (REPLETAGROUP, MULLERI SUBGROUP)

The metaphase and salivary gland chromosomes of Drosophila seriema wer e investigated in samples from seven different localities, which cover the known geographical range of the species. Very little chromosomal variability was found. A new karyotype was observed in two different l ocalities and, in addition, the fifth chromosome was found to be polym orphic for a small paracentric inversion in one of the stocks. Thus th is species appears to be essentially monomorphic, with low interpopula tional differentiation, at least at the chromosomal level, in comparis on with other species of the buzzatii complex. The phylogenetic relati onships of D. seriema with its nearest relatives are discussed. Here w e expand the forementioned studies of the metaphase and polytene chrom osomes. In addition, we analyzed the polytene chromosomes of the hybri d larvae from the cross between D. serienna and D. bouborema. This all owed a direct comparison of the chromosomal arrangements between these two species.