Patterns of molecular evolution associated with repeatedly evolved traits

Genetic sequence data were collected from the database GenBank or other sources. Study 1: sequences represented either marine, inland saline, and freshwater eukaryote lineages. Study 2: sequences represented freshwater and terrestrial-inhabiting insect lineages. Rates of molecular evolution were compared between habitat categories using a phylogenetic framework obtained from published studies of the taxa. Study 3: sequences (available on GenBank) for hexapod lineages were tested for positive and relaxed selection in association with the origin and loss of flight ability.本研究的遗传序列数据采集自GenBank（基因序列数据库）及其他相关来源。研究1：所纳入的序列涵盖海洋、内陆咸水与淡水真核生物演化支系。研究2：所纳入的序列涵盖淡水及陆生昆虫演化支系。本研究基于已发表的类群系统发育框架，对不同生境类群间的分子进化速率展开比较分析。研究3：针对可从GenBank数据库获取的六足动物演化支系序列，本研究检验了其与飞行能力起源及丧失相关联的正向选择与松弛选择效应。