Journal Article

intra- and inter-island study of the polytene chromosomes of Simulium exasperans (Diptera: Simuliidae)

Spironello, M, Hunter, F.F

2004

Overview

The polytene chromosome banding pattern of Simulium exasperans (Craig, 1987) is described for the first time. Three populations of S. exasperans from Moorea and Tahiti were examined cytologically. Interspecific comparisons revealed that S. exasperans is homosequential in chromosomal banding pattern to Simulium cataractarum (Craig, 1987), but contains three species-characteristic floating inversions: IL-1 ex .2 ex , IIL-1 ex ,2 ex , and IIIL-1 ex . No sex-linked inversions were identified; males and females had undifferentiated sex chromosomes. The IIL-1 ex ,2 ex inversion was in Hardy-Weinberg disequilibrium in two of the three populations. From this preliminary data, two cytotypes may exist: cytotype A (Belvedre Cascade population) and cytotype B (1st Afareaitu Cascade and Jardin Public Vaipahi populations). Contrary to phylogenetic and biogeographic data, it is hypothesized that the Belvedre Cascade population (cytotype A) is ancestral to the populations containing cytotype B. Furthermore, a heterozygote advantage may exist in cytotype B.

• Publisher: NRC Research Press,National Research Council of Canada,Canadian Science Publishing NRC Research Press
• Subject: Animal populations / Biological and medical sciences / chromosome banding / chromosome inversions / chromosome morphology / Chromosomes / Cortaderia / cytotypes / Fundamental and applied biological sciences. Psychology / geographical variation / Insecta / Insects / inversion polymorphism / Invertebrates / Islands / Morphology. Histology. Cytology / polytene chromosomes / sex chromosomes / Sexes / Simuliidae / Simulium / Simulium exasperans / Society Islands (French Polynesia) / Tahiti / Zoology