Chromosomal location and evolution of a satellite DNA family in seven sturgeon species

The Hind III satellite DNA family, isolated from the Acipenser naccarii gen ome, was used as a probe for fluorescent in-situ hybridization (FISH) on th e karyotype of seven sturgeon species, six belonging to the genus Acipenser and one to Huso. All species except one (A. sturio) exhibit from 8 to 80 c hromosome hybridization signals, mainly localized at the pericentromeric re gions. Eight chromosomes with weak hybridization signals are present in H. huso and A. ruthenus, which are characterized by a karyotype with about 120 chromosomes. The species with 240-260 chromosomes, A. transmontanus, A nac carii, A. gueldenstaedtii, and A. baerii, show from 50 to 80 signals, preva lently localized around centromeres. Moreover, A. transmontanus and A. guel denstaedtii show from 4 to 8 chromosomes with a double signal. The phylogen etic and evolutionary relationships among sturgeon species are discussed on the basis of number and morphology of signal-bearing chromosomes and on th e localization of signals.