The scale degeneration is thought to be related to the adaptation to the extreme environment with cold climate and high-altitude in schizothoracine fishes. Gymnocypris eckloni, a schizothoracine fish living in plateau waters with the elevation above 2500 m, is nearly esquamate and only covered with shoulder scales and anal scales, making it a good model species to study the molecular mechanism of scale degeneration. The transcriptomes of shoulder scaled skins (SSS), anal scaled skins (ASS) and scaleless skins (NSS) were sequenced and analyzed in G. eckloni at the age of 1 year. Histological examination showed that shoulder scale had completed its differentiation and anal scale just initiated the differentiation. A total of 578,046 unigenes were obtained from the transcriptomes, with 407,799 unigenes annotated in public databases. A total of 428 and 142 differentially expressed unigenes (DEUs) were identified between SSS and NSS, and between ASS and NSS, respectively, with 45 DEUs that were overlapped. Annotation analysis indicated that these DEUs were mainly enriched in Gene Ontology (GO) terms and KEGG pathways associated with bone and muscle formation, such as myofibril, contractile fiber, cytoskeletal protein binding, muscle structure development, cardiac muscle contraction, hypertrophic cardiomyopathy (HCM) and calcium signaling pathway. Our results would provide insights into the molecular mechanisms of scale degeneration in G. eckloni and other congeneric fishes. In addition, the transcriptome data provides candidate genes and markers for future studies.

中文翻译：

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鳞翅目裸鳞鱼鳞皮和无鳞皮的比较转录组分析为深入了解鳞屑变性的分子机理提供了见解

鳞片退化被认为与精神分裂症鱼类对极端气候，寒冷气候和高海拔环境的适应有关。裸Gym鱼（Gymnocypris eckloni）是生活在高原水域（海拔超过2500 m）的一种裂殖壶cine鱼，几乎处于鳞茎状态，仅被肩鳞和肛门鳞所覆盖，使其成为研究鳞屑退化的分子机制的良好模式物种。在1岁时，在G.eckloni中对肩鳞皮（SSS），肛门鳞皮（ASS）和无鳞皮（NSS）的转录组进行了测序和分析。组织学检查显示肩部鳞片已经完成分化，而肛门鳞片才开始分化。从转录组中总共获得578,046个单基因，在公共数据库中标注了407,799个单基因。在SSS和NSS之间以及ASS和NSS之间分别鉴定出总共428个和142个差异表达的单基因（DEU），其中45个DEU重叠。注释分析表明，这些DEU主要富含基因本体论（GO）术语和与骨骼和肌肉形成相关的KEGG途径，例如肌原纤维，收缩纤维，细胞骨架蛋白结合，肌肉结构发育，心肌收缩，肥厚型心肌病（HCM）和钙信号通路。我们的结果将为深入了解克氏菌和其他同类鱼类的鳞片退化的分子机制提供见解。另外，转录组数据提供了候选基因和标记，以供将来研究。分别有45个DEU重叠。注释分析表明，这些DEU主要富含基因本体论（GO）术语和与骨骼和肌肉形成相关的KEGG途径，例如肌原纤维，收缩纤维，细胞骨架蛋白结合，肌肉结构发育，心肌收缩，肥厚型心肌病（HCM）和钙信号通路。我们的结果将为深入了解克氏菌和其他同类鱼类的鳞片退化的分子机制提供见解。另外，转录组数据提供了候选基因和标记，以供将来研究。分别有45个DEU重叠。注释分析表明，这些DEU主要富含基因本体论（GO）术语和与骨骼和肌肉形成相关的KEGG途径，例如肌原纤维，收缩纤维，细胞骨架蛋白结合，肌肉结构发育，心肌收缩，肥厚型心肌病（HCM）和钙信号通路。我们的结果将为深入了解克氏菌和其他同类鱼类的鳞片退化的分子机制提供见解。另外，转录组数据提供了候选基因和标记，以供将来研究。细胞骨架蛋白结合，肌肉结构发育，心肌收缩，肥厚型心肌病（HCM）和钙信号通路。我们的结果将为深入了解克氏菌和其他同类鱼类的鳞片退化的分子机制提供见解。另外，转录组数据提供了候选基因和标记，以供将来研究。细胞骨架蛋白结合，肌肉结构发育，心肌收缩，肥厚型心肌病（HCM）和钙信号通路。我们的结果将为深入了解克氏菌和其他同类鱼类的鳞片退化的分子机制提供见解。另外，转录组数据提供了候选基因和标记，以供将来研究。