A recent polyploidy superimposed on older large-scale duplications in the Arabidopsis genome
A recent polyploidy superimposed on older large-scale duplications in the Arabidopsis genome
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DOI：
10.1101/gr.751803
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发表时间：
2003-02-01
期刊：
影响因子：
7
通讯作者：
Wolfe, KH
中科院分区：
文献类型：
--
作者：
Blanc, G;Hokamp, K;Wolfe, KH
拟南芥基因组包含许多大的重复染色体片段，但先前分析中使用的不同方法导致对祖先大规模重复事件的数量和时间有不同的解释。在此，我们使用更合适的方法以及基因组序列注释的更新版本，研究拟南芥中片段重复的规模和时间。我们利用蛋白质序列相似性搜索来检测基因组中的重复区块，使用重复基因之间的同义替换水平来估计包含它们的区块的相对年龄，并分析相邻重复区块之间的重叠程度。我们得出结论，拟南芥谱系至少经历了两次不同的重复事件。一次是多倍体化，其发生时间比先前估计的要近得多，在拟南芥/芜菁分裂之前，可能在十字花科早期出现期间（2400 - 4000万年前）。一组更古老的重复区块是在单子叶植物/双子叶植物分化之后形成的，这些区块之间相对较低的重叠程度表明，其中至少一些是诸如多倍体或非整倍体等更大规模重复的残余。
The Arabidopsis genome contains numerous large duplicated chromosomal segments, but the different approaches used in previous analyses led to different interpretations regarding the number and timing of ancestral large-scale duplication events. Here, using more appropriate methodology and a more recent version of the genome sequence annotation, we investigate the scale and timing of segmental duplications in Arabidopsis. We used protein sequence similarity searches to detect duplicated blocks in the genome, used the level of synonymous substitution between duplicated genes to estimate the relative ages of the blocks containing them, and analyzed the degree of overlap between adjacent duplicated blocks. We conclude that the Arabidopsis lineage underwent at least two distinct episodes of duplication. One was a polyploidy that occurred much more recently than estimated previously, before the Arabidopsis/Brassica rapa split and probably during the early emergence of the crucifer family (24-40 Mya). An older set of duplicated blocks was formed after the monocot/dicot divergence, and the relatively low level of overlap among these blocks indicates that at least some of them are remnants of a larger duplication such as a polyploidy or aneuploidy.