INVASION AND MAINTENANCE OF A GENE DUPLICATION
INVASION AND MAINTENANCE OF A GENE DUPLICATION
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DOI：
10.1073/pnas.91.8.2950
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发表时间：
1994-04-12
影响因子：
11.1
通讯作者：
CLARK, AG
中科院分区：
文献类型：
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作者：
CLARK, AG
多基因家族的普遍存在是基因重复频繁发生的证据，但多基因家族从单个基因起源仍然是基因组进化中一个研究较少的方面。虽然很明显，重复可以纯粹通过随机遗传漂变在种群中产生并固定下来，而且如果重复具有直接优势，其固定速率会加快，但基因重复的性质表明其他因素可能影响新重复的命运。面对有害的功能丧失突变，功能基因的重复可能为抵御此类突变提供一种缓冲。在此，利用单倍体和二倍体的正式群体遗传模型，推导出了从突变 - 选择平衡开始的罕见重复入侵的条件。反复重复可保护重复的染色体不丢失，并且在增加其在种群中的频率方面非常有效。在没有反复重复的情况下，人们可能会认为重复会受到自然选择的青睐，因为它可以掩盖有害突变的影响。然而，这些模型表明，只有当重复为生物体提供直接优势时，它才能入侵。这一结果与近期关于倍性进化的理论研究密切相关。
The ubiquity of multigene families is evidence for the frequent occurrence of gene duplication, but the origin of multigene families from a single gene remains a little-studied aspect of genome evolution. Although it is clear that a duplication can arise and become fixed in a population purely by random genetic drift and that the rate of fixation is accelerated ff the duplication is directly advantageous, the nature of gene duplication suggests that other factors may influence the fate of a novel duplication. In the face of disadvantageous loss-of-function mutations, duplication of a functional gene may provide a buffer against such mutations. Here the conditions for invasion of a rare duplication starting from a mutation-selection balance are derived with formal population genetic models in both haploids and diploids. Recurrent duplication protects the duplicated chromosome from loss and can be very effective in increasing its frequency in a population. In the absence of recurrent duplication, one might suppose that a duplication would be favored by natural selection because it can mask the effects of deleterious mutations. However, the models show that a duplication can invade only if it provides a direct advantage to the organism. This result is closely related to recent theoretical work on the evolution of ploidy.