title: Comparison of karyotypes of Acipenser oxyrinchus and A. sturio by chromosome banding and fluorescent in situ hybridization.
abstract: A highly debated problem in Acipenseridae taxonomy is whether Acipenser oxyrinchus (North American Atlantic sturgeon) and A. sturio (European Atlantic sturgeon) are true species: a detailed comparison of their karyotypes could provide relevant information. Here we describe for the first time the karyotype of A. oxyrinchus (2n = 121 +/- 3), and its features, among which the constitutive heterochromatin, revealed by C-banding technique, the distribution of telomeric regions, and the 5S rRNA genes, detected by FISH. The results reveal that A. oxyrinchus and A. sturio karyotypes and features are quite similar. Moreover, comparing the results obtained through hybridization by FISH with HindIII and PstI satellite DNA in these and in other sturgeon species, no hybridization signals are detected in A. sturio and A. oxyrinchus, while A. stellatus and A. gueldenstaedtii show hybridization. Thus A. sturio and A. oxyrinchus appear very similar from a cytogenetic point of view: these and molecular data repeatedly point out that A. sturio and A. oxyrinchus represent a sister clade in comparison to all other sturgeon species up to now studied.
authors.affiliation: Department of Biology, University of Ferrara, Via L. Borsari 46, 44100 Ferrara, Italy. francesco.fontana@unife.it
authors.forename: Francesco
authors.initials: F
authors.lastname: Fontana
authors.forename: Massimo
authors.initials: M
authors.lastname: Lanfredi
authors.forename: Frank
authors.initials: F
authors.lastname: Kirschbaum
authors.forename: Manuel A
authors.initials: MA
authors.lastname: Garrido-Ramos
authors.forename: Francisca
authors.initials: F
authors.lastname: Robles
authors.forename: Anna
authors.initials: A
authors.lastname: Forlani
authors.forename: Leonardo
authors.initials: L
authors.lastname: Congiu
mesh_terms: D000818:Animals; D002871:Chromosome Banding; D002875:Chromosomes / Q000235:genetics*; D004276:DNA, Satellite; D004076:Digoxigenin / Q000378:metabolism; D005399:Fishes / Q000235:genetics*; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D007621:Karyotyping; D008677:Metaphase; D011419:Propidium / Q000378:metabolism; D012341:RNA, Ribosomal, 5S; D013045:Species Specificity; D016615:Telomere
chemical_list: D004276:DNA, Satellite; D012341:RNA, Ribosomal, 5S; D011419:Propidium; D004076:Digoxigenin