Rapid evolution in a pair of recent duplicate segments of rice
Rapid evolution in a pair of recent duplicate segments of rice
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DOI：
10.1002/jez.b.21122
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发表时间：
2007-01-15
影响因子：
2.2
通讯作者：
Wang, Wen
中科院分区：
文献类型：
--
作者：
Jiang, Huifeng;Liu, Dongyuan;Wang, Wen
基因复制一直被认为是产生基因新颖性的最重要方式。基因复制后的后续进化对于新功能的产生至关重要。在这里，我们分析了水稻11号和12号染色体之间最近复制的片段的进化模式。这种重复事件估计发生在大约600万年前，当时B-基因组和C-基因组水稻物种的分化。12号染色体重复片段的序列重排频率显著高于非重复区域。重排的速率类似于每百万年6.5个断裂/Mb，大约是迄今报道的真核生物中最快的速率的6倍。这两个片段中的基因都经历了加速的核苷酸替换速率，表现为水稻和水稻之间的同义差异(K，)和非同义差异(K，，)。使用EST数据的分析也暗示了这些节段重复基因之间表达的快速差异。从不同角度来看，这些总体上的快速变化首次提供了证据，表明选择的放松也发生在大规模复制中。
Gene duplication has been considered the most important way of generating genetic novelties. The subsequent evolution right after gene duplication is critical for new function to occur. Here we analyzed the evolutionary pattern for a recently duplicated segment between rice chromosomes 11 and 12. This duplication event was estimated to occur about 6 million years ago, during the divergence of the B- and C-genome rice species. The duplicate segment in chromosome 12 has significantly higher frequency of sequence rearrangement rate than non-duplicated regions. The rearrangement rate is similar to 6.5 breakages/Mb per million years, about six times higher than the fastest rate ever reported in eukaryotes. The genes within both segments experienced accelerated nucleotide substitution rates revealed by synonymous (K,) and non-synonymous divergence (K,,) between Oryza sativa indica and O. sativa japonica. Analysis using EST data also implicates rapid divergence in expression between these segmental duplicate genes. These overall rapid changes from different perspective for the first time provide evidence that relaxation of selection also occurs in large-scale duplications.