CHROMOSOMAL-POLYMORPHISM IN NATURAL-POPULATIONS OF GLYPTOTENDIPES-PARIPES EDW (DIPTERA, CHIROMIDAE)

A comparative analysis of chromosomal polymorphism in four geographically isolated populations of Glyptotendipes paripes (Moscow, Novosibirsk, Tomsk, Yakutsk) is presented. Extremely high frequencies of homozygous and heterozygous inversions in chromosome I (perticularly in arm B) in association with very conserved band sequences in chromosomes II, III, IV were found. Two sequences (par A1 and par A2) in arm A of chromosome I in the heterozygote and homozygote and one, par A3, in the heterozygote were found. Six sequences were observed in arm B (three homozygotes and four heterozygotes). Comparisons of Hungarian, Bulgarian and Irkutsk populations described earlier (MICHAILOVA 1987) allowed us to identify three new sequences in arm B, a new one in arm A. Heteromorphism for a large heterochromatin block in the region 10 of chromosome I not previously described was revealed. Polymorphism in chromosomes II and III was demonstrated for the populations studied, although the frequencies of rearrangements in these chromosomes were much lower than in chromosome I. A new classification of band sequences for G. paripes is offered. The possible role of the identified chromosome rearrangements in the initial stages of sympatric species divergency is discussed.