The pattern of intron loss
The pattern of intron loss
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DOI：
10.1073/pnas.0408274102
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发表时间：
2005-01-18
影响因子：
11.1
通讯作者：
Gilbert, W
中科院分区：
文献类型：
--
作者：
Roy, SW;Gilbert, W
我们研究了来自7个完全测序的真核生物基因组的684组直向同源基因的内含子丢失。我们发现，更接近基因3'端的内含子优先丢失，如预测的，如果内含子通过用剪接mRNA的逆转录酶产物的基因转换丢失。相邻的内含子往往会同时丢失，如果这样的事件跨越多个内含子位置，这是预期的。与一些人的预期相反，不中断密码子（零阶段）的内含子更有可能丢失，而不是更少，这是一个有趣的和以前不受重视的结果。具有匹配相位的相邻内含子不太可能被保留，如果它们享有相对的选择优势，则会被预期。3'和零相内含子丢失偏倚的发现与最近对真菌内含子进化的研究直接矛盾。所有的模式是不太明显的血统，导致秀丽隐杆线虫，这表明，在线虫的内含子丢失的过程可能是定性不同的。我们的研究结果支持逆转录酶介导的内含子丢失模型。
We studied intron loss in 684 groups of orthologous genes from seven fully sequenced eukaryotic genomes. We found that introns closer to the 3' ends of genes are preferentially lost, as predicted if introns are lost through gene conversion with a reverse transcriptase product of a spliced mRNA. Adjacent introns tend to be lost in concert, as expected if such events span multiple intron positions. Directly contrary to the expectations of some, introns that do not interrupt codons (phase zero) are more, not less, likely to be lost, an intriguing and previously unappreciated result. Adjacent introns with matching phases are not more likely to be retained, as would be expected if they enjoyed a relative selective advantage. The findings of 3' and phase zero intron loss biases are in direct contradiction to an extremely recent study of fungi intron evolution. All patterns are less pronounced in the lineage leading to Caenorhabditis elegans, suggesting that the process of intron loss may be qualitatively different in nematodes. Our results support a reverse transcriptase-mediated model of intron loss.