A first karyological analysis of the sand goby, Oxyeleotris marmoratus (Teleostei, Eleotridae) in Thailand by Ag-NOR staining technique

Abstract

The standardized karyotype and idiogram of the sand goby (Oxyeleotris marmoratus) from Chi River in the Maha Sarakham Province of northeastern Thailand were studied. Kidney cell samples were taken from five male and five female fish. The mitotic chromosome preparations were prepared by blood cell culture and directly from kidney cells. Conventional and Ag-NOR staining techniques were applied to stain the chromosomes. The results showed that the diploid chromosome number of O. marmoratus was 2n = 46 and the fundamental number (NF) as 50 in both males and females. The types of chromosomes were 2 large submetacentric, 10 large telocentric, 2 medium metacentric and 32 medium telocentric chromosomes. No strange-sized chromosomes related to sex were observed. The region adjacent to the telomere of chromosome pair 7 showed clearly observable secondary constriction/NORs. The karyotype formula for O. marmoratus could be inferred as: 2n (diploid) 46 = L2 sm+Lt 10+M2 m+Mt 32.