MULTIPLE INDEPENDENT LOSSES OF 2 GENES AND ONE INTRON FROM LEGUME CHLOROPLAST GENOMES
MULTIPLE INDEPENDENT LOSSES OF 2 GENES AND ONE INTRON FROM LEGUME CHLOROPLAST GENOMES
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DOI：
10.2307/2419496
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发表时间：
1995-07-01
影响因子：
1
通讯作者：
PALMER, JD
中科院分区：
文献类型：
--
作者：
DOYLE, JJ;DOYLE, JL;PALMER, JD
叶绿体基因组中基因或内含子的丢失作为系统发育特征具有潜在的效用。先前对被子植物的广泛调查，以及对Pisum sativum的测序研究，发现了豆科植物中这些性状的几个变异实例。采用不需要高分子量DNA的槽点杂交方法，利用在被子植物叶绿体基因组中常见的sir基因和3个内含子探针，筛选了392个豆科属，代表了所有三个亚科和51个部落中的50个，以及其他26个豆科的48个属。在非豆科植物或豆科植物含豆亚科和含豆亚科中很少观察到叶绿体基因组中叶绿体基因或内含子丢失的情况，但在大亚科凤蝶亚科中观察到大量的叶绿体基因组丢失。某些疑似损失的病例用聚合酶链反应进行了检测。基因rp12和rbcL似乎存在于所有被调查的分类群中，并且几乎所有的分类群都具有accD。相比之下，ORF184和rps16似乎都在豆科中独立地丢失了多次，而该家族的所有成员似乎都缺乏rp122。在这个家族中，rp12的内含子可能至少丢失了四次，而它的缺失是一个核心群体的突触形态。在豆科植物中没有观察到令人信服的trnI和rpl16内含子丢失的证据。这些结果表明，基因或内含子丢失特征可能经常是同质性的。内含子丢失是一种比基因丢失更可靠、更有价值的系统发育特征。
The losses of genes or introns from the chloroplast genome are of potential utility as phylogenetic characters. Previous broad surveys of angiosperms, along with sequencing studies in Pisum sativum, uncovered several instances of variation for such characters within the Leguminosae. Using a slot blot hybridization method that did not require high molecular weight DNA, probes for sir genes and three introns typically found in angiosperm chloroplast genomes were used to screen 392 legume genera, representing all three subfamilies and 50 out of 51 tribes, and 48 genera from 26 other families of dicots. Few cases of chloroplast gene or intron loss from chloroplast genomes were observed among nonlegumes or within the legume subfamilies Mimosoideae and Caesalpinioideae, but numerous apparent losses were observed in the large subfamily Papilionoideae. Certain cases of suspected losses were tested by polymerase chain reaction. The genes rp12 and rbcL appear to be present in all taxa surveyed, and virtually all possess accD. In contrast, ORF184 and rps16 each appear to have been lost multiple, independent times within Leguminosae, while all members of the family appear to lack rp122. The intron of rp12 has likely been lost at least four times within the family, and its absence is a synapomorphy for a core group of the papilionoid tribe Desmodieae. No convincing evidence of loss was observed among legumes for the introns of trnI and rpl16. These results indicate that gene or intron loss characters may often be homoplastic. Intron losses are a more reliable and valuable class of phylogenetic characters than are gene losses.