Satellite DNA Evolution
Satellite DNA Evolution
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DOI：
10.1159/000337122
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发表时间：
2012-01-01
期刊：
影响因子：
--
通讯作者：
Mravinac, B.
中科院分区：
文献类型：
--
作者：
Plohl, M.;Mestrovic, N.;Mravinac, B.
卫星DNA是几乎所有真核生物基因组中最丰富的重复序列。卫星DNA单体的长阵列形成了密集排列的异染色质基因组隔间，也跨越了重要的着丝粒基因座。许多特定的特征可以归因于重复的基因组成分的进化。本章重点介绍卫星DNA的结构和进化动力学，以及导致它们构成的基因组区域快速变化的潜在分子机制。卫星DNA的单体序列通过分子驱动过程协调进化，在分子驱动过程中，突变在基因组中同质化并固定在种群中。这一过程导致在生殖隔离的生物群中卫星序列的差异。然而，一些卫星DNA序列在长时间的进化过程中是保守的。由于基因组中存在许多卫星DNA，物种特有的卫星DNA组成的进化可以通过一组物种共同的卫星序列文库中拷贝数的变化来指导。这些卫星DNA有两个重要特征：长时间序列保守性和通过拷贝数改变而倾向于快速变化。序列保守性可以通过诸如对卫星DNA分子的功能基序和/或结构特征施加的限制来加强。这些特征可以限制能够在基因组中持续存在的序列的选择，并可以指导跨越功能着丝粒的卫星DNA的进化过程。版权所有(C)2012 S.Karger AG，巴塞尔
Satellite DNAs represent the most abundant fraction of repetitive sequences in genomes of almost all eukaryotic species. Long arrays of satellite DNA monomers form densely packed heterochromatic genome compartments and also span over the functionally important centromere locus. Many specific features can be ascribed to the evolution of tandemly repeated genomic components. This chapter focuses on the structural and evolutionary dynamics of satellite DNAs and the potential molecular mechanisms responsible for rapid changes of the genomic areas they constitute. Monomer sequences of a satellite DNA evolve concertedly through a process of molecular drive in which mutations are homogenized in a genome and fixed in a population. This process results in divergence of satellite sequences in reproductively isolated groups of organisms. However, some satellite DNA sequences are conserved over long evolutionary periods. Since many satellite DNAs exist in a genome, the evolution of species-specific satellite DNA composition can be directed by copy number changes within a library of satellite sequences common for a group of species. There are 2 important features of these satellite DNAs: long time sequence conservation and, at the same time, proneness to rapid changes through copy number alterations. Sequence conservation may be enhanced by constraints such as those imposed on functional motifs and/or architectural features of a satellite DNA molecule. Such features can limit the selection of sequences able to persist in a genome, and can direct the evolutionary course of satellite DNAs spanning the functional centromeres. Copyright (C) 2012 S. Karger AG, Basel