Feasibility of nuclear ribosomal region ITS1 over ITS2 in barcoding taxonomically challenging genera of subtribe Cassiinae (Fabaceae)

Premise of the Study The internal transcribed spacer (ITS) region is situated between 18S and 26S in a polycistronic rRNA precursor transcript. It had been proved to be the most commonly sequenced region across plant species to resolve phylogenetic relationships ranging from shallow to deep taxonomic levels. Despite several taxonomical revisions in Cassiinae, a stable phylogeny remains elusive at the molecular level, particularly concerning the delineation of species in the genera Cassia, Senna and Chamaecrista. This study addresses the comparative potential of ITS datasets (ITS1, ITS2 and concatenated) in resolving the underlying morphological disparity in the highly complex genera, to assess their discriminatory power as potential barcode candidates in Cassiinae. Methodology A combination of experimental data and an in-silico approach based on threshold genetic distances, sequence similarity based and hierarchical tree-based methods was performed to decipher the discriminating powe...研究前提（Premise of the Study） 内部转录间隔区（internal transcribed spacer, ITS）位于多顺反子rRNA前体转录本的18S与26S区段之间。业已证实，ITS是植物类群中最常被用于测序的区域，可用于解析涵盖低阶到高阶分类阶元的系统发育关系。尽管决明亚族（Cassiinae）已历经多次分类学修订，但其分子层面的稳定系统发育关系仍未明确，尤其在决明属（Cassia）、番泻决明属（Senna）与山扁豆属（Chamaecrista）的物种界定方面尚存争议。本研究旨在探究ITS数据集（包含ITS1、ITS2及拼接序列）在解析该高度复杂类群潜在形态差异方面的比较价值，以评估其作为决明亚族候选DNA条形码的鉴别能力。 研究方法（Methodology） 本研究结合实验数据与基于阈值遗传距离、序列相似性及层级树法的计算机模拟（in-silico）分析策略，以解析其鉴别效力……