The effectiveness of mitochondrial rRNA gene sequences for the reconstruction of the phylogeny of an insect order (orthoptera)
The effectiveness of mitochondrial rRNA gene sequences for the reconstruction of the phylogeny of an insect order (orthoptera)
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DOI：
10.1006/mpev.1997.0425
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发表时间：
1997-10-01
影响因子：
4.1
通讯作者：
Rowell, CHF
中科院分区：
文献类型：
--
作者：
Flook, PK;Rowell, CHF
我们研究了线粒体rRNA序列在分析昆虫前新生代分歧事件中的价值。利用小亚基和大亚基rRNA序列从38直翅目物种，我们研究了几个方面的序列进化，包括二级结构，取代率，和碱基组成。从这两个基因计算的取代矩阵是非常相似的，虽然在二级结构中的配对和非配对位置之间的C-T转换率检测到差异。相比之下，在不同的系统发育水平的替代频率之间的极端差异，使字符过渡加权简约重建必不可少的。碱基组成分析表明，至少两个重要谱系的分支吸引是由于共享的碱基组成偏好和长分支吸引。值得注意的是，结合这两个序列似乎是合理的和必要的分类样本。然而，对于重建深分支的同源性，似乎增加分类群或核苷酸位置的数量之一或两者都不一定能解决所有问题。相反，使用mtDNA序列的古代分支事件的分辨率可能取决于更好的指定重建方法的开发和应用。(C)北京：科学出版社.
We investigated the value of mitochondrial rRNA sequences for analyzing pre-Cainozoic divergence events in insects. Using small subunit and large subunit rRNA sequences from 38 orthopteroid species, we examined several aspects of sequence evolution including secondary structure, substitution rate, and base composition. Substitution matrices calculated from the two genes were very similar, though differences were detected in rates of C-T transitions between paired and unpaired positions in secondary structures. By contrast, extreme disparities between substitution frequencies at different phylogenetic levels make character-transition weighting essential in parsimony reconstruction. The analysis of base composition indicated that branch attraction of at least two important lineages was due to shared base composition biases and to long branch attraction, The importance of taxonomic sampling and sequence length for the effectiveness of phylogenetic recovery using the rRNA fragments was also assessed. Significantly, combining the two sequences seemed both justifiable and necessary for this taxonomic sample. However, for reconstructing deep branches of phylogeny, it seems that increasing either or both the number of taxa or nucleotide positions will not necessarily solve all problems. Instead, the resolution of ancient branching events using mtDNA sequences probably depends upon the development and application of better specified reconstruction methods. (C) 1997 Academic Press.