Gene duplication has generally been viewed   as a necessary source of material for the origin of evolutionary novelties,   but it is unclear how often gene duplicates arise and how frequently they   evolve new functions. Observations from the genomic databases for several   eukaryotic species suggest that duplicate genes arise at a very high rate, on   average 0.01 per gene per million years. Most duplicated genes experience a   brief period of relaxed   selection early in their history, with a moderate fraction of them   evolving in an effectively neutral manner during this period. However, the   vast majority of gene duplicates are silenced within a few million years,   with the few survivors subsequently experiencing strong purifying selection.   Although duplicate genes may only rarely evolve new functions, the stochastic   silencing of such genes may play a significant role in the passive origin of   new species.

基因复制通常被视为进化新事物起源的必要物质来源，但尚不清楚基因重复出现的频率以及它们进化出新功能的频率。从几个真核生物的基因组数据库中观察到，重复基因的出现率非常高，平均每百万年每一个基因出现0.01次。大多数复制基因在其历史早期经历了一个短暂的松弛选择期，其中的一部分在这一时期以一种有效的中性方式进化。然而，绝大多数的基因重复在几百万年内被沉默，少数幸存者随后经历了强烈的纯化选择。尽管重复基因可能很少进化出新的功能，但这种基因的随机沉默可能在新物种的被动起源中发挥重要作用。