Centre for Integrative Genetics (CIGENE), Department of Animal and Aquacultural Sciences (IHA), Faculty of Life Sciences (BIOVIT), Norwegian University of Life Sciences (NMBU), PO Box 5003, 1433, Ås, Norway.
Nofima, PO Box 5010, N-1430, Ås, Norway.
Sci Rep. 2019 Jan 15;9(1):116. doi: 10.1038/s41598-018-36748-8.
The genetic mechanisms determining sex in teleost fishes are highly variable and the master sex determining gene has only been identified in few species. Here we characterize a male-specific region of 9 kb on linkage group 11 in Atlantic cod (Gadus morhua) harboring a single gene named zkY for zinc knuckle on the Y chromosome. Diagnostic PCR test of phenotypically sexed males and females confirm the sex-specific nature of the Y-sequence. We identified twelve highly similar autosomal gene copies of zkY, of which eight code for proteins containing the zinc knuckle motif. 3D modeling suggests that the amino acid changes observed in six copies might influence the putative RNA-binding specificity. Cod zkY and the autosomal proteins zk1 and zk2 possess an identical zinc knuckle structure, but only the Y-specific gene zkY was expressed at high levels in the developing larvae before the onset of sex differentiation. Collectively these data suggest zkY as a candidate master masculinization gene in Atlantic cod. PCR amplification of Y-sequences in Arctic cod (Arctogadus glacialis) and Greenland cod (Gadus macrocephalus ogac) suggests that the male-specific region emerged in codfishes more than 7.5 million years ago.
在硬骨鱼类中，决定性别分化的遗传机制具有高度的多样性，而主控性别决定基因仅在少数物种中被鉴定出来。在这里，我们在大西洋鳕鱼（Gadus morhua）的第 11 号连锁群上鉴定出一个 9kb 的雄性特异性区域，该区域包含一个名为 zkY 的 Y 染色体上的锌指基因。对表型性别已确定的雄性和雌性个体进行的诊断性 PCR 测试证实了 Y 序列的性别特异性。我们鉴定出了 12 个与 zkY 高度相似的常染色体基因拷贝，其中 8 个编码含有锌指结构域的蛋白质。3D 建模表明，在 6 个拷贝中观察到的氨基酸变化可能会影响假定的 RNA 结合特异性。鳕鱼 zkY 和常染色体蛋白 zk1 和 zk2 具有相同的锌指结构，但只有 Y 染色体特异性基因 zkY 在性别分化开始之前的发育幼虫中高水平表达。这些数据共同表明 zkY 可能是大西洋鳕鱼中的一个候选主控雄性化基因。对北极鳕鱼（Arctogadus glacialis）和格陵兰鳕鱼（Gadus macrocephalus ogac）的 Y 序列的 PCR 扩增表明，雄性特异性区域在鳕鱼中出现的时间超过 750 万年前。
