State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China.
Yunnan Key Laboratory of Plateau Fish Breeding, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China.
Int J Mol Sci. 2019 Feb 21;20(4):944. doi: 10.3390/ijms20040944.
Body size is one of the most important attributes of a species, but the basic question of why and how each species reaches a different "right size" is still largely unknown. Herein, three phylogenetically closely related catfishes from Sisoridae, including one extraordinarily large-sized and two average-sized and , were comparatively studied using RNA-Seq. Approximately 17,000 protein-coding genes were annotated for each of the three fishes, and 9509 genes were identified as high-confidence orthologous gene pairs. Comparative expressions uncovered a similar functional cluster about ribosome biogenesis was enriched in different tissues of the upregulated genes of . Moreover, differentially expressed genes and positively selected genes revealed that the glycolysis/pyruvate metabolism and cell cycle pathways have also greatly enhanced in this large-sized species. In total, 20 size-related candidate genes (including two growth modulators: the serine/threonine-protein kinases 3 () and adaptor protein 1 (), and a crucial pyruvate kinase ()) were identified by multiplying comparative analyses along with gene functional screening, which would play major roles in enabling the large body size associated with and provide new insights into body size evolution. In conjunction with field observations and morphological comparisons, we hypothesize that habitat preferences promote size divergence of sisorids.
体型是物种最重要的特征之一，但每个物种如何达到不同的“最佳体型”这一基本问题在很大程度上仍然未知。本研究中，我们比较研究了来自鲶形目鮡科的三种亲缘关系非常密切的鮡鱼，包括一种体型异常大的和两种体型中等的 。对这三种鱼中的每一种都进行了 RNA-Seq 注释，鉴定出了大约 17000 个编码蛋白的基因，其中 9509 个基因被鉴定为高可信度的直系同源基因对。比较表达分析揭示了核糖体生物发生相关的功能簇在 的上调基因的不同组织中富集。此外，差异表达基因和正选择基因表明，这个大型物种中的糖酵解/丙酮酸代谢和细胞周期途径也得到了极大的增强。通过综合比较分析和基因功能筛选，总共鉴定出了 20 个与体型相关的候选基因（包括两个生长调节剂：丝氨酸/苏氨酸蛋白激酶 3 () 和衔接蛋白 1 ()，以及一个关键的丙酮酸激酶（）），这些基因在使 具有较大体型方面发挥着重要作用，并为体型进化提供了新的见解。结合野外观察和形态比较，我们假设栖息地偏好促进了鮡科鱼类体型的分化。
