The organization, expression, and evolution of antibody genes and other multigene families.
The organization, expression, and evolution of antibody genes and other multigene families.
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抗体基因和其他多基因家族的组织、表达和进化。
DOI：
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发表时间：
1975
影响因子：
11.1
通讯作者：
S. C. Elgin
中科院分区：
文献类型：
--
作者：
L. Hood;J. Campbell;S. C. Elgin
多基因家族是染色体组织的一个单位。其基因成员紧密相连，序列同源，功能重叠。根据不同的结构和功能标准，多基因家族可分为三类：简单序列、多基因和信息基因。多基因家族表现出两个新的进化特征--巧合进化和家庭规模的快速变化--这表明它们都有一个或多个进化机制。自然选择不能直接作用于一个家族中的单个基因，因为它们的功能相同或重叠；因此，选择必须对整个家族或家族内的基因块起作用。巧合进化的机制(S)扩展了一个家族内的变异基因，使它们可以受到自然选择的影响，从而允许多基因家族自适应进化。多基因家族中的控制机制似乎促进了许多基因拷贝的快速表达。相反，信息家族的调控机制促进了适当信息单位的选择、表达和放大。一个家族中基因的紧密联系似乎是因为它们的控制和进化机制可能只作用于紧密相连的基因。新的多基因家族可能由单基因进化而来，也可能由其他多基因家族进化而来。除了进化出新的功能外，后一种进化模式还产生了一个新的多基因家族，其成员被预先适应以与旧家族的成员相互作用。这些家族相互作用可能导致更复杂的分子机器的进化，或者导致一个家族被另一个家族调控。多基因家族可以是大的也可以是小的。多基因家族的三种分类使潜在的多基因家族得以识别，并为新家族的研究提供了具体的实验方法。目前正在研究的一些最有趣的遗传系统是已知的或潜在的信息性多基因家族。这并不是偶然的，因为表型的许多最有趣的方面都是复杂的，具有相应复杂的遗传、进化和调控要求。现代遗传学的前沿之一是识别、表征和理解信息性多基因家族。
The multigene family is a unit of chromosomal organization. Its gene members are closely linked, homologous in sequence, and have overlapping functions. Multigene families can be divided into three catagories: simple-sequence, multiplicational, and informational-by a variety of structural and functional criteria. Multigene families exhibit two novel evolutionary features-coincidental evolution and rapid change in family size-that suggest that they all share one or more evolutionary mechanisms. Natural selection cannot act directly upon individual genes in a family because of their identical or overlapping functions; hence selection must operate upon the family as a whole or upon blocks of genes within the family. The mechanism(s) for coincidental evolution expands out variant genes within a family so they can be acted upon by natural selection and, accordingly, permits multigene families to evolve adaptively. The control mechanisms in multiplicational families appear to promote the rapid expression of many gene copies. In contrast, the regulatory mechanisms of informational families promote the selection, expression, and amplification of appropriate units of information. The close linkage of the genes in a family appears to be a consequence of the fact that their control and evolutionary mechanisms may only operate on tandemly linked genes. New multigene families may evolve from a single gene or from other multigene families. In addition to evolving new functions, the latter mode of evolution generates a new multigene family whose members are preadapted to interact with those of the old family. These family interactions can lead to the evolution of more sophisticated molecular machines or to the regulation of one family by a second. Multigene families may be large or small. The three catagories of multigene families allow potential multigene families to be identified, and they suggest specific experimental approaches for the study of new families. Some of the most interesting genetic systems under the investigation today are known or potential informational multigene families. This is not fortuitous in that many of the most interesting aspects of phenotype are complex ones with correspondingly complex genetic, evolutionary, and regulatory requirements. One of the frontiers in modern genetics is the identification, characterization, and understanding of informational multigene families.