A key metabolic gene for recurrent freshwater colonization and radiation in fishes
A key metabolic gene for recurrent freshwater colonization and radiation in fishes
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DOI：
10.1126/science.aau5656
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发表时间：
2019-05-31
期刊：
影响因子：
56.9
通讯作者：
Kitano, Jun
中科院分区：
文献类型：
--
作者：
Ishikawa, Asano;Kabeya, Naoki;Kitano, Jun
新生态位的殖民化引发了大规模的适应辐射。虽然一些血统已经利用了这样的机会，但并不是所有的都这样做。造成这种血统之间的差异的因素在很大程度上是未知的。在这里，我们表明，缺乏二十二碳六烯酸（DHA），一种必需的w-3脂肪酸，可以限制淡水殖民海洋鱼类。我们的基因组分析揭示了多个独立的重复的脂肪酸去饱和酶基因Fads 2在刺鱼谱系，随后殖民和辐射在淡水栖息地，但不是在近亲未能殖民。Fads 2在海洋棘鱼中的转基因操作增加了它们合成DHA的能力，并在缺乏DHA的饮食中生存。多种淡水辐鳍鱼的Fads 2拷贝也表现出趋同增加，这表明它在淡水定居中发挥着关键作用。
Colonization of new ecological niches has triggered large adaptive radiations. Although some lineages have made use of such opportunities, not all do so. The factors causing this variation among lineages are largely unknown. Here, we show that deficiency in docosahexaenoic acid (DHA), an essential w-3 fatty acid, can constrain freshwater colonization by marine fishes. Our genomic analyses revealed multiple independent duplications of the fatty acid desaturase gene Fads2 in stickleback lineages that subsequently colonized and radiated in freshwater habitats, but not in close relatives that failed to colonize. Transgenic manipulation of Fads2 in marine stickleback increased their ability to synthesize DHA and survive on DHA-deficient diets. Multiple freshwater ray-finned fishes also show a convergent increase in Fads2 copies, indicating its key role in freshwater colonization.