Standardized Karyotype and Idiogram of Two-Spot Glass Catfish, <i>Ompok bimaculatus</i> (Siluriformes, Siluridae) in Thailand by Conventional and Ag-NOR Staining Techniques

Abstract

Summary Standardized karyotype and idiogram of the two-spot glass catfish (Ompok bimaculatus) from Chi basin, Maha Sarakham Province, northeast Thailand, were studied. Kidney cell samples were taken from 5 male and 5 female fish. The mitotic chromosome preparations were prepared 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. bimaculatus was 2n=50, the fundamental number (NF) was 90 in both males and females. The types of chromosomes were 10 large metacentric, 2 large submetacentric, 4 large acrocentric, 2 large telocentric, 4 medium metacentric, 18 medium submetacentric, 2 medium acrocentric, 2 medium telocentric, and 6 small telocentric chromosomes. The region adjacent to telomere of the short arm of submetacentric chromosome pair 4 showed clearly observable nucleolar organizer regions (NORs

A First Chromosomal and Nucleolar Organizer Regions (NORs) Analyses of Chevey’s Sheetfish, <i>Micronema cheveyi</i> (Siluriformes, Siluridae)

“…All specimens investigated in the present study have telomeric NOR on the short arm of the submetacentric chromosome pair. The NOR position revealed is similar to other previous species studied in this family (Fujioka 1973, Ráb et al 1991, 1994, Khuda-Bukhsh and Das 2007, Verma et al 2011, Gomontier et al 2012. Thus, there is conservation for the ribosome synthesis genes loci in these catfishes.…”

“…The present cytogenetic study is also the new record in this genus. There are different from other species in the previous studies (Rishi 1976, Das and Kar 1977, Rishi and Singh 1983, Sharma and Tripathi 1984, Khuda-Bukhsh and Chanda 1989, Donsakul 1992, Datta et al 2003, Khuda-Bukhsh and Das 2007, Sharma 2008, Magtoon and Donsakul 2009, Verma et al 2011, Gomontier et al 2012. Compara-tive cytogenetic data among species of the family Siluridae in Thailand is displayed in the Table 1.…”

“…3). Two NOR-bearing chromosomes, there is agreeable with O. bimaculatus (Khuda-Bukhsh and Das 2007, Verma et al 2011, O. pabda (Verma et al 2011), O. siluriodes (Gomontier et al 2012), P. apogon (Supiwong et al 2012), Silurus aristotelis (Ráb et al 1994), Si. asotus (Fujioka 1973) and Si.…”

“…Robertsonian translocations may cause losses of NOR (Yüksel and Gaffaroğlu 2008). Up to the present, only 12 species have been cytogenetically investigated reporting the diploid chromosome number (2n) ranging from 40 to 92 chromosomes including S. phaiosoma, 2n= 40; S. schneideri, 2n= 40 (Magtoon and Donsakul 2009); O. siluriodes, 2n=50 (Donsakul 1992, Gomontier et al 2012; W. micropogon, 2n=56 (Donsakul 1996); O. fumidus, 2n= 60 (Magtoon and Donsakul 2009); B. truncatus, 2n= 62 (Donsakul 1996); K. macrocephalus, 2n= 62 (Magtoon and Donsakul 2009); K. bicirrhis, 2n= 64 (Donsakul 1996); P. apogon 2n= 64 (Supiwong et al 2012), P. bleekeri, 2n= 64 (Donsakul 1992; W. attu, 2n=86 from India (Rishi andSingh 1983, Sharma andTripathi 1984); 2n=88 from Thailand (Donsakul 1996) and K. cryptopterus, 2n=92 (Donsakul 1992).…”