Elder J F, Turner B J
Department of Biology, University of North Dakota Grand Forks 58202, USA.
Q Rev Biol. 1995 Sep;70(3):297-320. doi: 10.1086/419073.
A large fraction, sometimes the largest fraction, of a eukaryotic genome consists of repeated DNA sequences. Copy numbers range from several thousand to millions per diploid genome. All classes of repetitive DNA sequences examined to date exhibit apparently general, but little studied, patterns of "concerted evolution." Historically, concerted evolution has been defined as the nonindependent evolution of repetitive DNA sequences, resulting in a sequence similarity of repeating units that is greater within than among species. This intraspecific homogenization of repetitive sequence arrays is said to take place via the poorly understood mechanisms of "molecular drive." The evolutionary population dynamics of molecular drive remains largely unstudied in natural populations, and thus the potential significance of these evolutionary dynamics for population differentiation is unknown. This review attempts to demonstrate the potential importance of the mechanisms responsible for concerted evolution in the differentiation of populations. It contends that any natural grouping that is characterized by reproductive isolation and limited gene flow is capable of exhibiting concerted evolution of repetitive DNA arrays. Such effects are known to occur in protein and RNA-coding repetitive sequences, as well as in so-called "junk DNA," and thus have important implications for the differentiation and discrimination of natural populations.
真核生物基因组的很大一部分，有时甚至是最大部分，由重复DNA序列组成。每个二倍体基因组中的拷贝数从数千到数百万不等。迄今为止所研究的所有类型的重复DNA序列都表现出明显普遍但研究较少的“协同进化”模式。从历史上看，协同进化被定义为重复DNA序列的非独立进化，导致重复单元的序列相似性在种内大于种间。据说重复序列阵列的这种种内同质化是通过理解甚少的“分子驱动”机制发生的。分子驱动的进化种群动态在自然种群中仍 largely未被研究，因此这些进化动态对种群分化的潜在意义尚不清楚。本综述试图证明负责协同进化的机制在种群分化中的潜在重要性。它认为，任何以生殖隔离和有限基因流为特征的自然群体都能够表现出重复DNA阵列的协同进化。已知这种效应发生在蛋白质和RNA编码的重复序列以及所谓的“垃圾DNA”中，因此对自然种群的分化和鉴别具有重要意义。
