MRC Human Genetics Unit, The Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK.
BMC Biol. 2017 Aug 16;15(1):71. doi: 10.1186/s12915-017-0411-5.
Strong DNA conservation among divergent species is an indicator of enduring functionality. With weaker sequence conservation we enter a vast 'twilight zone' in which sequence subject to transient or lower constraint cannot be distinguished easily from neutrally evolving, non-functional sequence. Twilight zone functional sequence is illuminated instead by principles of selective constraint and positive selection using genomic data acquired from within a species' population. Application of these principles reveals that despite being biochemically active, most twilight zone sequence is not functional.
在不同物种中，高度保守的 DNA 是其功能持久的一个指标。随着序列保守性的减弱，我们进入了一个广阔的“暮光区”，在这个区域中，暂时或较低约束的序列与中性进化的非功能序列很难区分。相反，通过在一个物种的种群中获得的基因组数据，利用选择约束和正选择的原则，可以照亮暮光区功能序列。这些原则的应用表明，尽管大多数暮光区序列具有生物化学活性，但它们并没有功能。
