Fontana Francesco, Congiu Leonardo, Mudrak Vincent A, Quattro Joseph M, Smith Theodore I J, Ware Kent, Doroshov Serge I
Dipartimento di Biologia ed Evoluzione, Universita di Ferrara, Via L. Borsari, 46, 44100 Ferrara, Italy.
Genome. 2008 Feb;51(2):113-9. doi: 10.1139/g07-112.
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.
对短吻鲟（Acipenser brevirostrum）的三份重复样本进行了多种染色技术的核型分析。发现染色体数目为2n = 372 +/- 6。一个由374条染色体组成的代表性核型由178条中着丝粒/亚中着丝粒染色体以及196条端着丝粒/近端着丝粒染色体和微染色体组成。用HindIII卫星DNA探针进行荧光原位杂交（FISH）的信号在14条染色体上可见。用PstI卫星DNA探针获得的信号出现在12条染色体上。用5S rDNA探针进行的FISH在6条染色体上显示出荧光信号。与约120条染色体的物种中的2个信号以及240条染色体的物种中的4个信号相比，这些最新结果支持了短吻鲟是六倍体物种（可能起源于杂交）这一假说。基于这些结果，我们提出了一个模型，用以解释鲟鱼中通过杂交、基因组加倍和二倍体化发生的物种形成事件。
