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Title: Chromosome Study of Some Grasshopper Species from Different Localities in Central Ethiopia
Authors: Samuel, Berhanu
Advisors: Kifle Dagne(Dr.)
Keywords: Karyology
Central Ethiopia
Acridid grasshopper
Karyotypic conservatism,
chromosome
Copyright: Dec-2010
Date Added: 5-Jul-2012
Publisher: Addis Ababa University
Abstract: Hitherto, around 200 grasshopper species have been recorded in Ethiopia. Despite the diversity and economic importance of Ethiopian grasshoppers, the available information on their taxonomy, distribution and ecology is meager, and no report on the karyology of Ethiopian grasshoppers is available prior to this study. In this study, the karyotypes of ten taxa identified to different taxonomic levels are described. The studied grasshopper specimens were identified to belong to two families – Acrididae and Tetrigidae. Under Acrididae six genera – Acanthacris, Paracinema, Gastrimargus, Acrotylus, Pardalophora and Acrida were identified. Specimens of two additional taxa could not be identified beyond the family level. The specimens under the family Tetrigidae were found to belong to genus Paratettix. The grasshopper specimens were collected from eight localities in central Ethiopia. Chromosome preparations were made from tissues of the whole gut, 6 – 8 hours after the colchicine injection. The tissue was grinded in hypotonic solution (0.075M KCl). The suspension was centrifuged and the pellet was fixed in 3:1 methanol:acetic acid and followed by centrifugation. Air dry slide preparations were made from cell suspension. In some case the testis was used for the preparation of meiotic chromosomes following the same steps as in mitotic chromosome preparation. Slides were stained in Giemsa stain. Basically, all the studied species (Acanthacris spp., Paracinema tricolor, Gastrimargus spp., Acrida spp.-1, Acrida spp.-2, Acrotylus spp., Pardalophora spp., and the two unidentified specimens) belonging to the family Acrididae showed similarity in their karyotype, with all of them having 2n = 23 (22 autosomes + X) and 24 (22 autosomes + XX) telocentric chromosomes in male and female, respectively. Paratettix spp. (family Tetrigidae) had a different chromosome number, that is, 2n = 20 telocentric chromosomes. Furthermore, Acanthacris spp. showed some numerical instability of chromosomes in the mitotic and meiotic cells, and B chromosome like body was found in the meiotic cells of this specimen. Apart from the gross Karyotypic resemblance shown among the studied taxa of family Acrididae, slight variations in their karyotype have been noted between taxa of acridid grasshoppers. Further studies of the chromosomes of Ethiopian grasshoppers covering a wider geographic area and employing new cytological techniques were recommended.
Description: A Thesis Presented to the School of Graduate Studies, Addis Ababa University, in Partial Fulfillment of the Requirements for the Degree of Master of Science in Biology (Applied Genetics)
URI: http://hdl.handle.net/123456789/3282
Appears in:Thesis - Biology

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