Multiple L1 progenitors in prosimian primates: phylogenetic evidence from ORF1 sequences.
Multiple L1 progenitors in prosimian primates: phylogenetic evidence from ORF1 sequences.
复制标题
原猴灵长类动物中的多个 L1 祖细胞：来自 ORF1 序列的系统发育证据。
DOI：
10.1007/bf02407354
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发表时间：
1993
影响因子：
3.9
通讯作者：
Goodman,M
中科院分区：
文献类型：
--
作者：
Stanhope,MJ;Tagle,DA;Shivji,MS;Hattori,M;Sakaki,Y;Slightom,JL;Goodman,M
关于L1元件进化的不确定性之一是是否有许多祖先基因。我们目前的ORF1序列的缓慢洛里斯（Nycticebus coucang）和Galago（Galago crassicaudatus）的系统发育证据，有至少两个不同的祖先，活跃在同一时间，在这个家庭的原猴纲灵长类动物的祖先。一个最大的简约分析，包括代表性的L1从人类，兔子，和啮齿动物，沿着与原猴序列，发现一个galago L1（Gc11）分组非常强烈的慢洛里斯序列。其余的加拉哥元素形成了自己独特的和强有力的支持分支。最吝啬的树的每个链接的替换和沉默的网站变化的分析表明，在下降的Gc11序列大约两倍以上的同义取代比非同义的发生，这意味着Gc11创始人的功能一段时间后，分裂的galago和缓慢的洛里斯。强净化选择也明显的galago分支的树。这些数据表明，有两个不同的和同时期的L1祖先的懒猴类祖先，纯化选择下进化，保留作为功能的L1在galago血统（大概也在缓慢的洛里斯）。原猿ORF1序列可进一步细分为亚科。来自盔猴和懒猴洛里斯的ORF 1序列在3′端附近有一个提前终止的密码子，这是其他哺乳动物序列所不共有的，它使开放阅读框缩短了288 bp。对5′和3′部分的同义和非同义替换的分析，包括亚科内和亚科间的比较，以及其他哺乳动物序列之间的比较，表明这个提前终止密码子是原猴获得的，使这些灵长类动物中ORF 1的3′部分非编码。
One of the uncertainties regarding the evolution of L1 elements is whether there are numerous progenitor genes. We present phylogenetic evidence from ORF1 sequences of slow loris (Nycticebus coucang) and galago (Galago crassicaudatus) that there were at least two distinct progenitors, active at the same time, in the ancestor of this family of prosimian primates. A maximum parsimony analysis that included representative L1s from human, rabbit, and rodents, along with the prosimian sequences, revealed that one of the galago L1s (Gc11) grouped very strongly with the slow loris sequences. The remaining galago elements formed their own unique and strongly supported clade. An analysis of replacement and silent site changes for each link of the most parsimonious tree indicated that during the descent of the Gc11 sequence approximately two times more synonymous than nonsynonymous substitutions had occurred, implying that the Gc11 founder was functional for some time after the split of galago and slow loris. Strong purifying selection was also evident on the galago branch of the tree. These data indicate that there were two distinct and contemporaneous L1 progenitors in the lorisoid ancestor, evolving under purifying selection, that were retained as functional L1s in the galago lineage (and presumably also in the slow loris). The prosimian ORF1 sequences could be further subdivided into subfamilies. ORF1 sequences from both the galago and slow loris have a premature termination codon near the 3′ end, not shared by the other mammalian sequences, that shortens the open reading frame by 288 bp. An analysis of synonymous and nonsynonymous substitutions for the 5′ and 3′ portions, that included intra- and inter-subfamily comparisons, as well as comparisons among the other mammalian sequences, suggested that this premature stop codon is a prosimian acquisition that has rendered the 3′ portion of ORF1 in these primates noncoding.