Karyotype characterization of the stellate sturgeon, Acipenser stellatus, by chromosome banding and fluorescent in situ hybridisation.

A karyotype analysis by several staining techniques was carried out on the stellate sturgeon, Acipenser stellatus. The karyotype (2n = 146 +/- 6) comprised 37 pairs of meta submetacentric chromosomes; the others were acrocentrics and microchromosomes. The constitutive heterochromatin, revealed by C-banding technique, was localized in the pericentromeric region of all acrocentric chromosomes, including microchromosomes. The short arms of two large submetacentrics showed an intercalary band. The telomeric sequence ( TTAGGG)(n) detected by fluorescent in situ hybridization was localized at both ends of each chromosome. The hybridization signals with a Hind III satellite DNA family probe were visible as centromeric heterochromatin blocks on 10 chromosomes. After Ag-staining, the active nucleolar organizer regions were detected at one of the terminal regions of six chromosomes. In situ hybridization with the 28S rDNA probe revealed signals interspersed along the telomeric regions of eight chromosomes. After hybridization with the 5S probe, two signals were observed in two small chromosomes. Our data suggest that A. stellatus is a diploid species. CT 4th International Symposium on Strugeo