P.E. Pell

Comparative analysis of the polytene chromosomes of Glossina austeni and Glossina morsitans morsitans.

Polytene chromosome maps of the tsetse fly Glossina austeni have been prepared and a description of all the principal chromosome markers is provided. A detailed comparison has been effected between these chromosomes and the polytene elements of G. m. morsitans the only other member of the same sub-genus so far mapped. Although there are many similarities in banding pattern a relatively large number of paracentric inversions and at least one pericentric inversion separate the two species. There are also groups of bands in both species which are not shared in common.

The meiotic sequence in Glossina morsitans morsitans

Abstract The diploid chromosome number in those male G. m. morsitans examined is 2n = 8 ± 1 autosomes and the XY sex pair. Meiosis is almost certainly achiasmate and there is no recognizable diplotene or diakinesis. Only the 4 largest autosomes form bivalents (L1 and L2), the remaining small chromosomes appearing as univalents. These latter members are heterochromatic throughout prophase and they remain in close telomeric association throughout this phase. This is probably an adaptive mechanism ensuring their disjunction at 1st anaphase. The X and Y chromosomes differ both in length and centric location. They associate one with the other in an achiasmate manner via 2 small heterochromatic segments.

Polytene chromosomes of the tsetse fly Glossina morsitans morsitans.

Cytological maps have been prepared, and a detailed description is presented of all major markers in the polytene chromosomes of the tsetse fly Glossina morsitans morsitans, an important vector of African trypanosomiases. Only the five eu-chromosomes in males (L1 and L2 autosome pairs plus X chromosome) and the six eu-chromosomes in females of the species (L1, L2 and X chromosome pairs) form polytene elements. The group of heterochromatic S autosomes and the Y chromosome appear to be absent in polytene nuclei. The information contained in this paper may further the development of genetical control methods of tsetse flies, and should assist in phylogenetic analyses of the genus Glossina.