Transcriptome sequencing reveals genome-wide variation in molecular evolutionary rate among ferns

Background: Transcriptomics in non-model plant systems has recently reached a point where the examination of nuclear genome-wide patterns in understudied groups is an achievable reality. This progress is especially notable in evolutionary studies of ferns, for which molecular resources to date have been derived primarily from the plastid genome. Here, we utilize transcriptome data in the first genome-wide comparative study of molecular evolutionary rate in ferns. We focus on the ecologically diverse family Pteridaceae, which comprises about 10 % of fern diversity and includes the enigmatic vittarioid ferns—an epiphytic, tropical lineage known for dramatically reduced morphologies and radically elongated phylogenetic branch lengths. Using expressed sequence data for 2091 loci, we perform pairwise comparisons of molecular evolutionary rate among 12 species spanning the three largest clades in the family and ask whether previously documented heterogeneity in plastid substitution rates is r...研究背景：近年来，非模式植物的转录组学（Transcriptomics）研究已取得长足进展，如今对研究不足类群开展全核基因组模式分析已成为可实现的现实。这一进步在蕨类植物的进化研究中尤为显著——迄今为止，蕨类的分子资源主要源自质体基因组。本研究利用转录组数据，开展了首个针对蕨类植物分子进化速率的全基因组比较研究。我们聚焦于生态多样性丰富的凤尾蕨科（Pteridaceae）：该类群约占全球蕨类物种多样性的10%，其中包含神秘的书带蕨类（vittarioid ferns）——这是一类附生热带演化支，以形态极度简化、系统发育分支长度显著延长而著称。本研究利用2091个基因座的表达序列数据，对该科三大主要演化支涵盖的12个物种的分子进化速率进行两两比较，并探讨此前已报道的质体替换速率异质性是否...