Polyploidy in Bulinid Snails, with Emphasis on Bulinus truncatus/tropicus Complex (Planorbidae: Pulmonate Mollusks) from Various Localities in Ethiopia

Zekeria Yusuf, Kifle Dagne, Berhanu Erko, Ogheneochuko Siemuri

Breeding and Genetics, Haramaya University, Ethiopia

Breeding and Genetics, Addis Ababa, University, Ethiopia

Pathologist, Addis Ababa Univeristy, Ethiopia

Department of Biochemistry, Faculty of Science, Delta State University, Abraka, Nigeria

Accepted 25 September 2017

Citation: Yusuf Z, Dagne K, Erko B, Siemuri O (2017). Polyploidy in Bulinid Snails, with Emphasis on Bulinus Truncatus/Tropicus Complex (Planorbidae: Pulmonate Mollusks) from Various Localities in Ethiopia. World Journal of Cell Biology and Genetics 3(1): 011-020.

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Copyright: © 2017 Yusuf et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

Abstract

Freshwater snails of the genus Bulinus, mostly Bulinus truncatus/tropicus complex occur in Ethiopia in various ploidy levels (diploid, tetraploid, hexaploid and octoploid) which are otherwise rare in other animal phyla. This study provides data on the occurrence and distribution of various ploidy levels of  B. truncatus/tropicus complex in Ethiopia based on meiotic bivalent chromosome counts. Emphasis was made on the role of shell morphology and chromosome number in species identification of B.truncatus /tropicus group. Specimens were collected from fourteen different localities in Ethiopia. Chromosome preparation was made from gonad tissue (ovotestis). The result showed that diploid species are mainly associated with low altitude, tetraploid with both low and medium altitudes whereas hexaploids and octoploids with high altitudes. Unexpected result was found in Lake Hora, where both diploid and tetraploid populations were occurring together in the same microhabitat which is in contrary to suggestions of some authors that two cytotypes of Bulinus truncatus/ tropicus complex do not occur in the same water body in Ethiopia. It was recommended that thorough investigation of each water body where snails are occurring, should be undertaken using cytological and molecular approaches and that the possibility of hexaploid Bulinussnails as potential host of human schistosome parasites in the highland of Ethiopia. 

Key words: bivalent chromosome number, Bulinus truncatus/tropicus complex, gonad tissue (ovotestis),  ploidy level.