Multiple independent losses of the rpoC1 intron in angiosperm chloroplast DNA's
Multiple independent losses of the rpoC1 intron in angiosperm chloroplast DNA's
复制标题
DOI：
10.2307/2419744
复制
发表时间：
1996-04-01
影响因子：
1
通讯作者：
KatzDownie, DS
中科院分区：
文献类型：
--
作者：
Downie, SR;Llanas, E;KatzDownie, DS
先前的研究表明，在地钱属、黑松和迄今为止检测的绝大多数被子植物中，叶绿体基因 rpoC1 被一个内含子（约 750 个碱基 Fairs）中断，但在禾本科植物和仙人掌三个亚科之一（Cactoideae）中，该内含子已经丢失。使用聚合酶链式反应 (PCR) 扩增了 107 个被子植物物种（代表 54 个科）的完整 rpoC1 内含子区域和部分侧翼外显子区域的 DNA，以发现内含子丢失的其他情况。除了草和仙人掌科叶绿体 DNA 之外，我们报告称，Scaeoola 和 Goodenia（古德尼亚科中仅有的两个代表）、西番莲属（西番莲科）十种中的四种、相思科四个属中的两个属（Delosperma 和 Faucaria，但不包括串珠属或串珠属）的叶绿体基因组中缺少 rpoC1 内含子。 Tetragonia），以及所检查的紫花苜蓿八个分类单元之一（M. suffruticosa subsp. leiocarpa；豆科）。序列分析显示，与叶绿体基因组中内含子丢失的其他实例相呼应，对于这些bra，rpoC1 基因已经经历了内含子的精确删除。对于那些具有内含子的类群，该区域内明显存在最小的大小变化，并且在所有研究的类群中，内含子位于基因中完全相同的位置。对部分外显子和内含子 rpoC1 核苷酸序列的简约分析表明，后者由于内含子测序区域的二级结构相当保守，可以为高分类水平的系统发育分析提供有用的特征。
Previous studies have shown that in Marchantia, black pine, and the vast majority of angiosperms examined to date, the chloroplast gene rpoC1 is interrupted by an intron (of about 750 base Fairs), but that in the grasses and one of three subfamilies of cacti (Cactoideae) this intron has been lost. DNA's of the complete rpoC1 intron region and portions of the flanking exon regions from 107 species (representing 54 families) of angiosperms were amplified with the polymerase chain reaction (PCR) in order to uncover other instances of intron loss. In addition to grass and Cactoideae chloroplast DNA's, we report that the rpoC1 intron is missing from the chloroplast genomes of Scaeoola and Goodenia (the only two representatives of Goodeniaceae examined), four of ten species of Passiflora (Passifloraceae), two of four genera of Aizoaceae (Delosperma and Faucaria but not Monilaria or Tetragonia), and one of the eight taxa of Medicago examined (M. suffruticosa subsp. leiocarpa; Fabaceae). Mirroring other instances of intron loss from the chloroplast genome, sequence analysis reveals that, for these bra, the rpoC1 gene has undergone a precise deletion of the intron. For those taxa with the intron, minimal size variation is apparent within the region and, in all taxa investigated, the intron lies in precisely the same position in the gene. Parsimony analyses of partial exon and intron rpoC1 nucleotide sequences reveal that the latter, owing to considerable conservation of secondary structure in that region of the intron sequenced, can supply useful characters for phylogenetic analysis at high taxonomic levels.