Iturra P, Lam N, de la Fuente M, Vergara N, Medrano J F
Facultad de Medicina, Programa de Genética Humana, ICBM, Universidad de Chile, Casilla, Santiago.
Genetica. 2001;111(1-3):125-31. doi: 10.1023/a:1013725717142.
With the aim of characterizing the sex chromosomes of rainbow trout (Oncorhynchus mykiss) and to identify the sex chromosomes of coho salmon (O. kisutch), we used molecular markers OmyP9, 5S rDNA, and a growth hormone gene fragment (GH2), as FISH probes. Metaphase chromosomes were obtained from lymphocyte cultures from farm specimens of rainbow trout and coho salmon. Rainbow trout sex marker OmyP9 hybridizes on the sex chromosomes of rainbow trout, while in coho salmon, fluorescent signals were localized in the medial region of the long arm of one subtelocentric chromosome pair. This hybridization pattern together with the hybridization of a GH2 intron probe on a chromosome pair having the same morphology, suggests that a subtelocentric pair could be the sex chromosomes in this species. We confirm that in rainbow trout, one of the two loci for 5S rDNA genes is on the X chromosome. In males of this species that lack a heteromorphic sex pair (XX males), the 5S rDNA probe hybridized to both subtelocentrics. This finding is discussed in relation to the hypothesis of intraspecific polymorphism of sex chromosomes in rainbow trout.
为了鉴定虹鳟（Oncorhynchus mykiss）的性染色体并确定银大麻哈鱼（O. kisutch）的性染色体，我们使用分子标记OmyP9、5S rDNA和生长激素基因片段（GH2）作为荧光原位杂交（FISH）探针。中期染色体取自虹鳟和银大麻哈鱼养殖样本的淋巴细胞培养物。虹鳟性别标记OmyP9在虹鳟的性染色体上杂交，而在银大麻哈鱼中，荧光信号定位于一对亚端部着丝粒染色体长臂的中间区域。这种杂交模式以及GH2内含子探针在具有相同形态的一对染色体上的杂交表明，一对亚端部着丝粒染色体可能是该物种的性染色体。我们证实，在虹鳟中，5S rDNA基因的两个位点之一位于X染色体上。在该物种缺乏异型性染色体对的雄性（XX雄性）中，5S rDNA探针与两个亚端部着丝粒染色体都发生了杂交。结合虹鳟性染色体内种多态性的假说对这一发现进行了讨论。
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