Positive selection in development and growth rate regulation genes involved in species divergence of the genus Radix

Background: Life history traits like developmental time, age and size at maturity are directly related to fitness in all organisms and play a major role in adaptive evolution and speciation processes. Comparative genomic or transcriptomic approaches to identify positively selected genes involved in species divergence can help to generate hypotheses on the driving forces behind speciation. Here we use a bottom-up approach to investigate this hypothesis by comparative analysis of orthologous transcripts of four closely related European Radix species. Results: Snails of the genus Radix occupy species specific distribution ranges with distinct climatic niches, indicating a potential for natural selection driven speciation based on ecological niche differentiation. We then inferred phylogenetic relationships among the four Radix species based on whole mt-genomes plus 23 nuclear loci. Three different tests to infer selection and changes in amino acid properties yielded a total of 134 genes wi...研究背景：在所有生物中，发育时长、成熟年龄与成熟体型等生活史性状（life history traits）均与适合度直接相关，且在适应性进化与物种形成过程中发挥核心作用。通过比较基因组学或转录组学方法鉴定参与物种分化的正选择基因，可为推导物种形成的驱动因子提供假说支撑。本研究采用自下而上的研究策略，通过对4个近缘欧洲椎实螺（Radix）物种的直系同源转录本进行比较分析，对该假说开展验证。 研究结果：椎实螺属（Radix）各物种均拥有物种特异性的分布范围与独特的气候生态位，提示基于生态位分化的自然选择具备驱动物种形成的潜在可能。随后，我们基于完整线粒体基因组（mt-genomes）与23个核基因座，推断了这4个椎实螺物种的系统发育关系。通过3种用于推断选择作用与氨基酸性质变化的不同检测方法，我们共获得134个基因……