Karyotype of Tilapia zillii (Gervais, 1848) from University of Ilorin reservoir, Ilorin, Nigeria

Abstract

There is paucity of data on the karyotype of Tilapia zillii in Nigeria. The present study was undertaken to determine the karyotype of T. zillii. Eight specimens of T. zillii were collected from the University of Ilorin reservoir located on the Southeastern part of the University. Each specimen was injected with 0.02% colchicine (1ml/100g body weight) and left for 4 hours. Chromosome preparation was done from the anterior kidney. Eighty mitotic metaphases were examined and the diploid chromosome number ranged from 42-48 per metaphase. The modal diploid number for T. zillii was found to be 2n=44 and this represented 53.75%. The chromosomes were of small size and aggregated in compact form. All the chromosomes were acrocentric. Sex chromosomes and polyploidy were not observed.