Modern techniques are revealing that repetition of segments of the genome, called amplification or gene amplification, is very common. Amplification is found in all domains of life, and occurs under conditions where enhanced expression of the amplified genes is advantageous. Amplification extends the range of gene expression beyond that which is achieved by control systems. It also is reversible because it is unstable, breaking down by homologous recombination. Amplification is believed to be the driving force in the clustering of related functions, in that it allows them to be amplified together. Amplification provides the extra copies of genes that allow evolution of functions to occur while retaining the original function. Amplification can be induced in response to cellular stressors. In many cases, it has been shown that the genomic regions that are amplified include those genes that are appropriate to upregulate for a specific stressor. There is some evidence that amplification occurs as part of a broad, general stress response, suggesting that organisms have the capacity to induce structural changes in the genome. This then allows adaptation to the stressful conditions. The mechanisms by which amplification arises are now being studied at the molecular level, but much is still unknown about the mechanisms in all organisms. Recent advances in our understanding of amplification in bacteria suggests new interpretations of events leading to human copy number variation, as well as evolution in general.

中文翻译：

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自适应放大。

现代技术表明，基因组片段的重复（称为扩增或基因扩增）非常普遍。扩增存在于生活的所有领域，并且在扩增的基因的增强表达是有利的条件下发生。扩增扩大了基因表达的范围，超出了控制系统所能达到的范围。它也是可逆的，因为它不稳定，会因同源重组而分解。放大被认为是相关功能聚类的驱动力，因为它使它们可以一起放大。扩增提供了额外的基因拷贝，这些拷贝允许在保持原始功能的同时进行功能进化。可以响应细胞应激物来诱导扩增。在很多情况下 已经显示，被扩增的基因组区域包括适合于特定应激源上调的那些基因。有证据表明，扩增是广泛的，普遍的应激反应的一部分，这表明生物体具有诱导基因组结构变化的能力。然后这允许适应压力条件。现在正在分子水平研究扩增产生的机理，但是对于所有生物中的机理仍知之甚少。我们对细菌扩增的理解的最新进展表明对导致人类拷贝数变异以及进化的事件的新解释。有证据表明，扩增是广泛的，普遍的应激反应的一部分，这表明生物体具有诱导基因组结构变化的能力。然后这允许适应压力条件。现在正在分子水平研究扩增产生的机理，但是对于所有生物中的机理仍知之甚少。我们对细菌扩增的理解的最新进展表明对导致人类拷贝数变异以及进化的事件的新解释。有证据表明，扩增是广泛的，普遍的应激反应的一部分，这表明生物体具有诱导基因组结构变化的能力。然后这允许适应压力条件。现在正在分子水平研究扩增产生的机理，但是对于所有生物中的机理仍知之甚少。我们对细菌扩增的理解的最新进展表明对导致人类拷贝数变异以及进化的事件的新解释。但是对于所有生物中的机制仍知之甚少。我们对细菌扩增的理解的最新进展表明对导致人类拷贝数变异以及进化的事件的新解释。但是对于所有生物中的机制仍知之甚少。我们对细菌扩增的理解的最新进展表明对导致人类拷贝数变异以及进化的事件的新解释。