Ulvophytes are attractive model systems for understanding the evolution of growth, development, and environmental stress responses. They are untapped resources for food, fuel, and high-value compounds. The rapid and abundant growth of Ulva species makes them key contributors to coastal biogeochemical cycles, which can cause significant environmental problems in the form of green tides and biofouling. Until now, the Ulva mutabilis genome is the only Ulva genome to have been sequenced. To obtain further insights into the evolutionary forces driving divergence in Ulva species, we analyzed 3 905 single copy ortholog family from U. mutabilis, Chlamydomonas reinhardtii and Volvox carteri to identify genes under positive selection (GUPS) in U. mutabilis. We detected 63 orthologs in U. mutabilis that were considered to be under positive selection. Functional analyses revealed that several adaptive modifications in photosynthesis, amino acid and protein synthesis, signal transduction and stress-related processes might explain why this alga has evolved the ability to grow very rapidly and cope with the variable coastal ecosystem environments.

藻类是吸引人的模型系统，可用于理解生长，发育和环境胁迫响应的演变。它们是用于食物，燃料和高价值化合物的未开发资源。Ulva物种的迅速而丰富的生长使其成为沿海生物地球化学循环的关键因素，这可能以绿潮和生物污染的形式引起严重的环境问题。到目前为止，Ulva mutabilis基因组是唯一已测序的Ulva基因组。为了进一步了解推动Ulva物种分化的进化力，我们分析了U. mutabilis，莱茵衣藻和Volvox Carteri的3 905个单拷贝直系同源物家族鉴定U. mutabilis中正选择（GUPS）基因。我们在U. mutabilis中检测到63个直系同源物，这些直系同源物被认为处于阳性选择之下。功能分析表明，在光合作用，氨基酸和蛋白质合成，信号转导和胁迫相关过程中的几种适应性修饰可能可以解释为什么这种藻类已经发展出能够快速生长并应对变化的沿海生态系统环境的能力。