Combinatorial DNA Rearrangement Facilitates the Origin of New Genes in Ciliates.
Combinatorial DNA Rearrangement Facilitates the Origin of New Genes in Ciliates.
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DOI：
10.1093/gbe/evv172
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发表时间：
2015-09-02
影响因子：
3.3
通讯作者：
Landweber LF
中科院分区：
文献类型：
--
作者：
Chen X;Jung S;Beh LY;Eddy SR;Landweber LF
单细胞真核生物三叶草（Oxytricha trifallax）的程序性基因组重排在发育过程中从其种系细胞核的拷贝中产生转录活跃的体细胞核。这一过程消除了生殖系基因组中中断编码区域的非编码序列，并连接了超过225,000个剩余的DNA片段，其中一些片段需要倒置或复杂的排列才能构建功能基因。这种动态的基因组组织允许生殖系中的一些DNA片段通过不同的加工形成多个不同的体细胞基因。与替代mRNA剪接一样，DNA片段的组合组装有助于遗传变异并促进新基因的进化。在这项研究中，我们使用比较基因组分析来证明替代DNA剪接的出现与新基因的起源有关。短时间的复制会产生与共享基因片段拼接的替代基因片段。替代基因片段比共享的组成部分进化得更快。具有共享片段的基因通常具有不同的表达谱，从而允许功能分化。本研究报道了选择性DNA剪接作为新基因起源的一种机制，说明了程序化的基因组重排过程如何引起进化创新。
Programmed genome rearrangements in the unicellular eukaryote Oxytricha trifallax produce a transcriptionally active somatic nucleus from a copy of its germline nucleus during development. This process eliminates noncoding sequences that interrupt coding regions in the germline genome, and joins over 225,000 remaining DNA segments, some of which require inversion or complex permutation to build functional genes. This dynamic genomic organization permits some single DNA segments in the germline to contribute to multiple, distinct somatic genes via alternative processing. Like alternative mRNA splicing, the combinatorial assembly of DNA segments contributes to genetic variation and facilitates the evolution of new genes. In this study, we use comparative genomic analysis to demonstrate that the emergence of alternative DNA splicing is associated with the origin of new genes. Short duplications give rise to alternative gene segments that are spliced to the shared gene segments. Alternative gene segments evolve faster than shared, constitutive segments. Genes with shared segments frequently have different expression profiles, permitting functional divergence. This study reports alternative DNA splicing as a mechanism of new gene origination, illustrating how the process of programmed genome rearrangement gives rise to evolutionary innovation.