Chromosomal Characteristic of Nile Tilapia (Oreochromis niloticus) from Mitotic and Meiotic Cell Division by T-Lymphocyte Cell Culture

Chromosomal characteristics of Nile tilapia (Oreochromis niloticus) from mitotic and meiotic cell division were studied. Blood samples were taken from five male and five female fish. Fish chromosome preparation was conducted by T-lymphocyte cell culture and squash technique from testis. The chromosomes were stained by conventional and Ag-NOR staining techniques. The results showed that the diploid chromosome number of O. niloticus was 2n=44 and the fundamental number (NF) was 58 in both male and female. The types of chromosomes were present as 2 large acrocentric, 2 small submetacentric, 10 small acrocentric, and 30 small telocentric chromosomes. There are no strange size chromosomes related to sex. We also observed distinctive secondary constriction/NORs at the region adjacent to the short arms near telomere of a pair of submetacentric chromosomes. The karyotype formula of O. niloticus is as stated: 2n (diploid) 42=La2+S2sm+Sa10+St30.