The nucleolar organizer regions (NORs) in the mitotic chromosomes of tilapia Oreochromis niloticus were analyzed using silver nitrate staining Ag detected NORs(Ag NORs) in the chromosomes of the tilapia exhibited he...The nucleolar organizer regions (NORs) in the mitotic chromosomes of tilapia Oreochromis niloticus were analyzed using silver nitrate staining Ag detected NORs(Ag NORs) in the chromosomes of the tilapia exhibited heteromorphism. Individual Ag NORs sizes varied on different chromosomes, and the number of Ag NOR per cell varied from three to six. Among the examined 100 cells, 71% of the gnomes carried four Ag NORs, 12% carried 3,11% carried 5, and 6% carried 6. The variance occurred not only among different cells but also among different cells from the same source. The satellite association between homologous chromosomes in No 7 was also observed in 27% of the metaphase chromosome preparations. The heteromorphic properties of Ag NORs were discussed.展开更多
文摘The nucleolar organizer regions (NORs) in the mitotic chromosomes of tilapia Oreochromis niloticus were analyzed using silver nitrate staining Ag detected NORs(Ag NORs) in the chromosomes of the tilapia exhibited heteromorphism. Individual Ag NORs sizes varied on different chromosomes, and the number of Ag NOR per cell varied from three to six. Among the examined 100 cells, 71% of the gnomes carried four Ag NORs, 12% carried 3,11% carried 5, and 6% carried 6. The variance occurred not only among different cells but also among different cells from the same source. The satellite association between homologous chromosomes in No 7 was also observed in 27% of the metaphase chromosome preparations. The heteromorphic properties of Ag NORs were discussed.
