Browsing by Author "Jegede, Oladele Ilesanmi"

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Open Access
    Karyotypes of Gymnarchus Niloticus Cuvier and Pollymyrus Petricolous Daget(Osteoglossiformes) from Oluwa river,Ondo state ,Nigeria
    (zoology,Obafemi Awolowo University, 2013) Jegede, Oladele Ilesanmi
    ABSTRACT The karyotypes of Gymnarchus niloticus Cuvier and Pollimyrus petricolus Daget from Oluwa River, Okitipupa, Ondo State were investigated to determine their diploid numbers and characteristics. This was with a view to assessing the chromosomal pattern and evolution of karyotypes in the order Osteoglossiformes. Mitotic cells obtained from kidney and gill tissues of G. niloticus and P. petricolus were arrested at metaphase stage by injecting the specimens intraperitoneally with 0.05% colchicines. Hypotonic treatment was in 0.075 M potassium chloride, while prepared slides were stained with 8% Giemsa in 6.8 pH phosphate buffer. The slides were viewed under a binocular light microscope (Leical Gallen III model), and the pictures of cells with good metaphase spread obtained using a digital camera (AmScope MT version 3.0.0.1) mounted on the microscope. Chromosome arms were measured from enlarged computer prints of the best metaphase spread. Karyotyping was made from photo prints of the digital photographs and idiogram plotted using Microsoft Office Excel. G. niloticus had a karyotype of 2n = 54; 24m+20sm+10sta (FN = 98), while a karyotype of 2n = 48; 10m+18sm+20sta (FN = 76) was recorded for P. petricolus. A tetraploid cell (4n = 96) was found in P. petricolus. This study concluded that the karyotype obtained for G. niloticus, provided a cytogenetic basis for the separation of G. niloticus from the family Mormyridae into a separate family, the Gymnarchidae.