Comparative karyological studies on [tilapia fish] oreochromis species

An attempt was made to study the karyological differences among three of Oreochromis species nominated Tilapia nilotica [O. niloticus], Tilapia aurea [O. aureus] and Tilapia galilae [O. galileus]. The diploid number of chromosomes were 22 pairs in all species, in which one was a large acrocentric pair for each species. The 22 pairs of chromosomes have nearly similar length and centromere location in all three species. This similarity in genetic make-up allows cross- breeding and hybrid vigor production among these three Oreochromis species and this is also responsible for similarity in feeding, breeding and biological behavior among them