The mitochondrial genome and transcriptome of the basal dinoflagellate Hematodinium sp.: character evolution within the highly derived mitochondrial genomes of dinoflagellates.
The mitochondrial genome and transcriptome of the basal dinoflagellate Hematodinium sp.: character evolution within the highly derived mitochondrial genomes of dinoflagellates.
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DOI：
10.1093/gbe/evr122
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发表时间：
2012
影响因子：
3.3
通讯作者：
Waller RF
中科院分区：
文献类型：
--
作者：
Jackson CJ;Gornik SG;Waller RF
姐妹门甲藻和顶复门继承了一个急剧减少的线粒体基因组（线粒体DNA，mtDNA），只含有三个蛋白质编码（cob，cox1和cox3）基因和两个核糖体RNA（rRNA）基因。在顶复门中，这些基因的单拷贝编码在已知最小的mtDNA染色体（6 kb）上。然而，在腰鞭毛虫中，基因组经历了进一步的实质性修改，包括大规模的基因组扩增和重组，导致每个基因的多个拷贝和基因片段以多种组合连接。此外，蛋白质编码基因已经失去了标准的终止密码子，需要信使RNA（mRNA）的反式剪接来产生完整的cox3转录本，并且广泛的RNA编辑重新编码大多数基因。从迄今为止研究的分类群来看，还不清楚这些不寻常的甲藻mtDNA特征是何时进化的。为了解决这个问题，我们研究了线粒体基因组和转录组字符状态的深分支甲藻血甲藻属。基因组数据显示，像后期分支甲藻血甲藻属也包含一个膨胀的，大量重组的基因组的多拷贝基因和基因片段。虽然cox1和cob也缺少终止密码子，但cox3仍然编码常规的终止密码子。大量的编辑的mRNA也发生在血甲藻的mtDNA的基础甲藻血甲藻表明，甲藻的mtDNA修饰发生在这个谱系的早期，包括基因组扩增和重组，并减少使用标准的终止密码子。反式剪接，另一方面，发生后血甲藻分歧。只有RNA编辑在甲藻中呈现出非线性的进化模式，因为这一过程发生在血甲藻中，但在一些后期分支类群中不存在，这表明这一过程要么在某些谱系中丢失，要么在非常不寻常的甲藻mtDNA进化过程中不止一次发展。
The sister phyla dinoflagellates and apicomplexans inherited a drastically reduced mitochondrial genome (mitochondrial DNA, mtDNA) containing only three protein-coding (cob, cox1, and cox3) genes and two ribosomal RNA (rRNA) genes. In apicomplexans, single copies of these genes are encoded on the smallest known mtDNA chromosome (6 kb). In dinoflagellates, however, the genome has undergone further substantial modifications, including massive genome amplification and recombination resulting in multiple copies of each gene and gene fragments linked in numerous combinations. Furthermore, protein-encoding genes have lost standard stop codons, trans-splicing of messenger RNAs (mRNAs) is required to generate complete cox3 transcripts, and extensive RNA editing recodes most genes. From taxa investigated to date, it is unclear when many of these unusual dinoflagellate mtDNA characters evolved. To address this question, we investigated the mitochondrial genome and transcriptome character states of the deep branching dinoflagellate Hematodinium sp. Genomic data show that like later-branching dinoflagellates Hematodinium sp. also contains an inflated, heavily recombined genome of multicopy genes and gene fragments. Although stop codons are also lacking for cox1 and cob, cox3 still encodes a conventional stop codon. Extensive editing of mRNAs also occurs in Hematodinium sp. The mtDNA of basal dinoflagellate Hematodinium sp. indicates that much of the mtDNA modification in dinoflagellates occurred early in this lineage, including genome amplification and recombination, and decreased use of standard stop codons. Trans-splicing, on the other hand, occurred after Hematodinium sp. diverged. Only RNA editing presents a nonlinear pattern of evolution in dinoflagellates as this process occurs in Hematodinium sp. but is absent in some later-branching taxa indicating that this process was either lost in some lineages or developed more than once during the evolution of the highly unusual dinoflagellate mtDNA.
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影响因子：
14.9
作者：
Feagin, JE;Mericle, BL;Morris, M
通讯作者：
Morris, M
影响因子：
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作者：
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通讯作者：
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作者：
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