蕨类植物psaA基因的分子进化研究

采用“放松分子钟”模型、氨基酸位点正选择模型和分子内共进化网络估算方法，对蕨类植物光合系统Ⅰ核心蛋白PSAA编码基因psaA的进化趋势进行了研究。结果显示，叶绿体基因psaA编码区全序列具备成为蕨类植物系统发育关系重建位点的潜力，与rbcL基因联合后能构建高后验概率的系统发育树；蕨类植物的PSAA蛋白中存在一些曾经历正选择的氨基酸位点，其中29个位点聚合成为16个共进化组，通过共进化网络的方式协同影响光合系统Ⅰ的内部调整，提升其在被子植物兴起后光合环境下的适应能力。本文对蕨类植物进化潜能与分子机理的研究结果为揭示蕨类植物适应新生境提供了科学依据，也为植物系统分类学研究提供了分子依据。

Study on the molecular evolution of the psaA gene from ferns

The psaA gene is a fundamental protein-coding gene of photosystem Ⅰ. Using the relaxed molecular clock model, positive selection model, and co-evolutionary analysis, we attempted to unravel its evolutionary pattern. Results indicated that the full-length coding sequences of psaA from fern species could be novel sites for the reconstruction of phylogenetic trees, and could exhibit high posterior probability when combined with the full-length coding sequences of rbcL. The current research also illustrated that the PSAA protein had 29 positively selected amino-acid sites aggregated into 16 co-evolution groups, indicating that ferns had internally modified their photosystem Ⅰ to enhance their ability to adapt to the photosynthetic environment after the rise of angiosperms.