Comparative karyotype study of three Cyprinids (Cyprinidae, Cyprininae) in Thailand by classical cytogenetic and FISH techniques.

Abstract

Three species of ornamental fishes in the subfamily Cyprininae (family Cyprinidae) namely, Epalzeorhynchos frenatum (Fowler, 1934), Puntigrus partipentazona (Fowler, 1934), Scaphognathops bandanensis Boonyaratpalin et Srirungroj, 1971 were studied by classical cytogenetic and fluorescent in situ hybridization (FISH) techniques. Chromosomes were directly prepared from kidney tissues and stained by using conventional and Ag-NOR banding techniques. Microsatellite d(CA)₁₅ and d(CGG)₁₀ probes were hybridized to the chromosomes of three cyprinids. The results show that the three cyprinid species share the same diploid number as 2n=50 but there are differences in the fundamental number (NF) and karyotypes i.e. E. frenatum: NF = 78, 18m+10sm+10st+12a; P. partipentazona: NF = 80, 6m+24sm+14st+6a; S. bandanensis: NF = 66, 4m+12sm+34a. NOR positive masks were observed at the regions adjacent to the telomere of the short arm of the chromosome pairs 10 (submetacentric) and 1 (metacentric) in E. frenatum and P. partipentazona, respectively whereas those were revealed at telomeric regions of the long arm of the chromosome pair 9 (acrocentric) in S. bandanensis. The mapping of d(CA)₁₅ and d(CGG)₁₀ microsatellites shown that hybridization signals are abundantly distributed in telomeric regions of several pairs except d(CA)₁₅ repeats in S. bandanensis, which are distributed throughout all chromosomes and d(CGG)₁₀ repeats in P. partipentazona display the high accumulation only in the first chromosome pair.