Chromosome Study of Some Fish Species from Rift Valley Lakes and Some Other Water Bodies of Ethiopia
No Thumbnail Available
Date
2008-07
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
Fishes are the most diverse of the major vertebrate groups. However, cytogenetic studies
in fish have not been well studied globally as well as here in Ethiopia. Five species
belonging to four families were sampled randomly from rift valley lakes and some water
bodies; and their mitotic chromosomes have been studied or determined using splashing
method. For chromosome preparation, each live fish specimen was injected with
colchicine (0.5% of 0.8/100 gm body weight) and kept alive for 6-8 hours. The gill
filaments were removed and kept in hypotonic solution (0.75M KCL) for about 30
minutes and then were fixed in 3:1(methanol: glacial acetic acid) for 30 minutes. Gill
filaments were grinded with 1-1.5 ml of fixative solution and filtered with gauze. Finally
the cell solution centrifugation for 5 minutes and air-dry slide preparation was made and
stained in Giemsa. Photographs were taken from the best metaphase plates of each
specimen and chromosome numbers were determined. The result showed that, the
chromosome numbers of (2n) obtained for Tilapia zilli (2n=44), Oreochromis niloticus
(2n=44), Clarias gariepinus (2n=56), Synodontis schall (2n=54), and Carassius auratus
(2n= 94) all except the last fish specimen are in agreement with the previous reports.
Since karyotypic analysis could not be given to all species under the present study, it is
better to carry out further cytological study in the future to get more reliable chromosome
data for better understanding about their taxonomic and evolutionary relationships.
Key Words: - Fish, Tilapia, Oreochromis, Clarias, Synodontis, Carassius, diploid
chromosome number, Rift Valley lakes, Ethiopia.
Description
Keywords
Fish, Tilapia, Oreochromis, Clarias, Synodontis, Carassius, diploid chromosome number, Rift Valley lakes, Ethiopia.