Genomic and biochemical evidence of dietary adaptation in a marine herbivorous fish.
Genomic and biochemical evidence of dietary adaptation in a marine herbivorous fish.
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DOI：
10.1098/rspb.2019.2327
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发表时间：
2020-02-26
期刊：
影响因子：
--
通讯作者：
German, Donovan P
中科院分区：
文献类型：
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作者：
Heras, Joseph;Chakraborty, Mahul;German, Donovan P
采用新的饮食是一个重大的进化变化，可以深刻地影响动物的生理，生物化学，生态和基因组。为了研究这种进化转变，我们研究了一种衍生的草食性鱼类，Cebidichthys violaceus的消化生理和基因组学。我们对该菌的基因组（N50 = 6.7 Mb）和消化转录组进行了测序和组装，揭示了消化酶（糖酶、蛋白酶和脂肪酶）的分子变化，发现了丰富的分子适应证据。具体而言，两个基因家族经历了拷贝数和适应性氨基酸取代的扩张：淀粉酶和羧基酯脂肪酶（cel），它们分别参与碳水化合物和脂质的消化。两者都显示基因表达水平升高和酶活性增加。由于棘背鱼的饮食中含有丰富的碳水化合物，而脂质很少，这些发现表明，这种饮食专业化既涉及利用丰富的资源，也涉及清除稀有的资源，特别是必需的营养素，如必需脂肪酸。
Adopting a new diet is a significant evolutionary change, and can profoundly affect an animal's physiology, biochemistry, ecology and genome. To study this evolutionary transition, we investigated the physiology and genomics of digestion of a derived herbivorous fish, Cebidichthys violaceus. We sequenced and assembled its genome (N50 = 6.7 Mb) and digestive transcriptome, and revealed the molecular changes related to digestive enzymes (carbohydrases, proteases and lipases), finding abundant evidence of molecular adaptation. Specifically, two gene families experienced expansion in copy number and adaptive amino acid substitutions: amylase and carboxyl ester lipase (cel), which are involved in the digestion of carbohydrates and lipids, respectively. Both show elevated levels of gene expression and increased enzyme activity. Because carbohydrates are abundant in the prickleback's diet and lipids are rare, these findings suggest that such dietary specialization involves both exploiting abundant resources and scavenging rare ones, especially essential nutrients, like essential fatty acids.