title: Evidence of hexaploid karyotype in shortnose sturgeon.
abstract: A karyotype analysis by several staining techniques was carried out on triplicate samples of the shortnose sturgeon, Acipenser brevirostrum. The chromosome number was found to be 2n = 372 +/- 6. A representative karyotype of 374 chromosomes was composed of 178 metacentrics/submetacentrics and 196 telocentrics/acrocentrics and microchromosomes. The signals of fluorescent in situ hybridization (FISH) with a HindIII satellite DNA probe were visible on 14 chromosomes. The signals obtained with a PstI satellite DNA probe appeared on 12 chromosomes. The FISH with a 5S rDNA probe revealed fluorescent signals on 6 chromosomes. These last results, compared with 2 signals in species with about 120 chromosomes and 4 in species with 240, support the hypothesis that A. brevirostrum is a hexaploid species, probably of hybrid origin. Based on these results, we propose a model explaining speciation events occurring in sturgeons by hybridization, genome duplication, and diploidization.
authors: Dipartimento di Biologia ed Evoluzione, Universita di Ferrara, Via L. Borsari, 46, 44100 Ferrara, Italy. francesco.fontana@unife.it
authors: Francesco
authors: F
authors: Fontana
authors: Leonardo
authors: L
authors: Congiu
authors: Vincent A
authors: VA
authors: Mudrak
authors: Joseph M
authors: JM
authors: Quattro
authors: Theodore I J
authors: TI
authors: Smith
authors: Kent
authors: K
authors: Ware
authors: Serge I
authors: SI
authors: Doroshov
mesh_terms: D000818:Animals; D004275:DNA, Ribosomal / Q000235:genetics; D005399:Fishes / Q000235:genetics*; D020440:Gene Duplication; D016678:Genome; D007621:Karyotyping; D008938:Mitosis; D009693:Nucleic Acid Hybridization; D011123:Polyploidy
chemical_list: D004275:DNA, Ribosomal