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牛津大学一项研究得出结论认为我们的DNA中只有8.2%有可能做一些重要的事情。其余的都是无用DNA，一种进化遗留产物，很像盲肠，没有任何好处，但也没有任何害处。 |
牛津大学一项研究得出结论认为我们的DNA中只有8.2%有可能做一些重要的事情。其余的都是无用DNA，一种进化遗留产物，很像盲肠，没有任何好处，但也没有任何害处。其中很大一部分不做任何事情。
这项研究的联合首席研究员Gurton Lunter博士说：“绝大多数是坐在那里无所事事，它占用空间。”
先前估计我们的DNA中有80%是‘有用的’或者做一些有用的事。“从医学角度讲，这是必不可少的解释人类疾病中遗传变异的作用”。而研究人员在比较了我们与其他哺乳动物的DNA后提出8.2%的估计，并寻找虽然经历了数百万年的进化任然保持不变的区块。
这种没有变化被看作为一种标志它做着一些重要的事情。更重要的是，虽然通常认为我们的DNA充满了基因，但是8%中只有超过1%是有用的遗传物质。其他的7%左右是散落着的控制这些基因的开关。
研究人员Chris Rands 说：“我们往往倾向于我们所有的DNA都必须做点什么。而现实是只有一小部分有功能。”(来源：生物帮)
原文摘要：
Chris M. Rands, Stephen Meader, Chris P. Ponting, Gerton Lunter
Ten years on from the finishing of the human reference genome sequence, it remains unclear what fraction of the human genome confers function, where this sequence resides, and how much is shared with other mammalian species. When addressing these questions, functional sequence has often been equated with pan-mammalian conserved sequence. However, functional elements that are short-lived, including those contributing to species-specific biology, will not leave a footprint of long-lasting negative selection. Here, we address these issues by identifying and characterising sequence that has been constrained with respect to insertions and deletions for pairs of eutherian genomes over a range of divergences. Within noncoding sequence, we find increasing amounts of mutually constrained sequence as species pairs become more closely related, indicating that noncoding constrained sequence turns over rapidly. We estimate that half of present-day noncoding constrained sequence has been gained or lost in approximately the last 130 million years (half-life in units of divergence time, d1/2 = 0.25–0.31). While enriched with ENCODE biochemical annotations, much of the short-lived constrained sequences we identify are not detected by models optimized for wider pan-mammalian conservation. Constrained DNase 1 hypersensitivity sites, promoters and untranslated regions have been more evolutionarily stable than long noncoding RNA loci which have turned over especially rapidly. By contrast, protein coding sequence has been highly stable, with an estimated half-life of over a billion years (d1/2 = 2.1–5.0). From extrapolations we estimate that 8.2% (7.1–9.2%) of the human genome is presently subject to negative selection and thus is likely to be functional, while only 2.2% has maintained constraint in both human and mouse since these species diverged. These results reveal that the evolutionary history of the human genome has been highly dynamic, particularly for its noncoding yet BioLogically functional fraction.