Adaptation and evolution of deep-sea scale worms (Annelida: Polynoidae): insights from transcriptome comparison with a shallow-water species.
Adaptation and evolution of deep-sea scale worms (Annelida: Polynoidae): insights from transcriptome comparison with a shallow-water species.
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DOI：
10.1038/srep46205
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发表时间：
2017-04-11
影响因子：
4.6
通讯作者：
Qiu JW
中科院分区：
文献类型：
--
作者：
Zhang Y;Sun J;Chen C;Watanabe HK;Feng D;Zhang Y;Chiu JM;Qian PY;Qiu JW
大约6000万年前，Polynoid scale worms（Polynoidae，Annelida）入侵了深海化学合成生态系统，但对它们对极端深海环境的遗传适应知之甚少。本文报道了深海多角虫Branchipolynoepettiboneae和Lampionotopodium sp.的前两个转录组。并将其与浅水多聚体（Harmothoe imbricata）的转录组进行比较。我们确定了密码子和氨基酸的使用，阳性选择基因，高表达基因和假定的重复基因。转录组组装在三个物种中产生了98，806至225，709个重叠群。有更多的带正电荷的氨基酸（即，组氨酸和精氨酸）和带较少负电荷的氨基酸（即，天冬氨酸和谷氨酸）。有120个基因显示出明确的正选择证据。在10%的最高表达基因中，两种深海物种中有更多的血红蛋白基因具有高表达水平。与DNA重组、代谢和基因表达相关的重复基因仅在深海物种中富集。在以化学合成为基础的生境中，深海鳞虫采取了两种适应缺氧的策略（即，在Branchipolynoe中四结构域血红蛋白的快速进化或在Lanconotopodium sp.中单结构域血红蛋白的高表达）。
Polynoid scale worms (Polynoidae, Annelida) invaded deep-sea chemosynthesis-based ecosystems approximately 60 million years ago, but little is known about their genetic adaptation to the extreme deep-sea environment. In this study, we reported the first two transcriptomes of deep-sea polynoids (Branchipolynoe pettiboneae, Lepidonotopodium sp.) and compared them with the transcriptome of a shallow-water polynoid (Harmothoe imbricata). We determined codon and amino acid usage, positive selected genes, highly expressed genes and putative duplicated genes. Transcriptome assembly produced 98,806 to 225,709 contigs in the three species. There were more positively charged amino acids (i.e., histidine and arginine) and less negatively charged amino acids (i.e., aspartic acid and glutamic acid) in the deep-sea species. There were 120 genes showing clear evidence of positive selection. Among the 10% most highly expressed genes, there were more hemoglobin genes with high expression levels in both deep-sea species. The duplicated genes related to DNA recombination and metabolism, and gene expression were only enriched in deep-sea species. Deep-sea scale worms adopted two strategies of adaptation to hypoxia in the chemosynthesis-based habitats (i.e., rapid evolution of tetra-domain hemoglobin in Branchipolynoe or high expression of single-domain hemoglobin in Lepidonotopodium sp.).