Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3QX, United Kingdom.
Annu Rev Genomics Hum Genet. 2011;12:275-99. doi: 10.1146/annurev-genom-090810-183115.
The amount of a genome's sequence that is functional has been surprisingly difficult to estimate accurately. This has severely hindered analyses asking whether the amount of functional genomic sequence correlates with organismal complexity. Most studies estimate these amounts by considering nucleotide substitution rates within aligned sequences. These approaches show reduced power to identify sequence that is aligned, functional, and constrained only within narrowly defined phyla. The neutral indel model exploits insertions or deletions (indels) rather than substitutions in predicting functional sequence. Surprisingly, this method indicates that half of all functional sequence is specific to individual eutherian lineages. This review considers the rates at which coding or noncoding and functional or nonfunctional sequence changes among mammalian genomes. In contrast to the slow rate at which protein-coding sequence changes, functional noncoding sequence appears to change or be turned over at rapid rates in mammals.
基因组序列中具有功能的部分的数量一直难以准确估计。这严重阻碍了分析功能基因组序列的数量是否与生物体的复杂性相关的研究。大多数研究通过比较对齐序列中的核苷酸替换率来估计这些数量。这些方法在识别仅在狭义定义的门内对齐、功能和受约束的序列方面的能力较弱。中性插入缺失模型利用插入或缺失（插入缺失）而不是替换来预测功能序列。令人惊讶的是，这种方法表明，所有功能序列的一半都是特定于单个真兽类谱系的。这篇综述考虑了哺乳动物基因组中编码或非编码、功能或非功能序列变化的速率。与蛋白质编码序列变化的缓慢速率相比，功能非编码序列在哺乳动物中似乎以快速速率发生变化或被替换。
