# 编者信息 熊荣川 明湖实验室 xiongrongchuan@126.com http://blog.sciencenet.cn/u/Bearjazz Theory suggests three alternative outcomes in the evolution of duplicate genes: (i) one copy may simply become silenced by degenerative mutations (nonfunctionalization); (ii) one copy may acquire a novel, beneficial function and become preserved by natural selection, with the other copy retaining the original function (neofunctionalization); or (iii) both copies may become partially compromised by mutation accumulation to the point at which their total capacity is reduced to the level of the single-copy ancestral gene (subfunctionalization) (1–12). Because the vast majority of mutations affecting fitness are deleterious (13), and because gene duplicates are generally assumed to be functionally redundant at the time of origin, virtually all models predict that the usual fate of a duplicate-gene pair is the nonfunctionalization of one copy. The expected time that elapses before a gene is silenced is thought to be relatively short, on the order of the reciprocal of the null mutation rate per locus (a few million years or less), except in populations with enormous effective sizes (11, 12). 理论表明，在重复基因的进化过程中，有三种不同的结果：（ i ）一个拷贝可能被退化的突变（非功能化）所沉默；（ ii ）一个拷贝可能获得一种新的、有益的功能（新功能化），并被自然选择所保留，而另一个拷贝则保留了原来的功能；或（ iii ）两个拷贝可能因突变累积而部分表达，直至其总容量降低到单拷贝祖先基因的水平（子功能化）（ 1-12 ）。因为影响适应能力的绝大多数突变是有害的（ 13 ），并且由于基因重复在起源时通常被认为是功能上的冗余，几乎所有的模型都预测一个重复基因对的通常命运是一个拷贝的非功能化。除了具有巨大个体数的群体（ 11 ， 12 ），考虑每个基因座的不同无义突变率级别（几百万年或更少），基因沉默前的预期时间被认为是相对较短的。 Lynch, M. The Evolutionary Fate and Consequences of Duplicate Genes . Science, 2000, 290(5494):1151-1155.
标签: 基因拷贝
