REPETITIVE DNA AND CHROMOSOME EVOLUTION IN PLANTS
REPETITIVE DNA AND CHROMOSOME EVOLUTION IN PLANTS
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DOI：
10.1098/rstb.1986.0004
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发表时间：
1986-01-29
影响因子：
6.3
通讯作者：
FLAVELL, RB
中科院分区：
文献类型：
--
作者：
FLAVELL, RB
大多数高等植物基因组包含高比例的重复序列。因此，重复DNA是植物染色体结构的主要贡献者。物种间总DNA含量的差异主要是由于重复DNA含量的差异。同一家族的一些重复序列在异染色质位点上串联排列。本文描述了来自鳞甲属植物的例子。相同序列的阵列经常出现在许多染色体位点上。异染色质通常包含几个不相关序列的阵列。讨论了这种阵列在种群中的演化。其他重复序列分散在染色体的许多位置。许多可能是或已经从转座因子进化而来。介绍了一些植物转座因子的结构，特别是末端反向重复序列。大豆、抗鼻草和玉米中部分元件具有相同的末端反向重复序列。玉米和小麦的其他成分与酵母、果蝇、人和小鼠的成分具有末端同源性。讨论了植物群体中转座因子的进化。在进化过程中，不同重复DNA序列的扩增、删除和转位以及突变在群体中的传播产生了重复DNA的周转。这一翻转过程及其分子机制被讨论并证明是物种间染色体结构分化的原因。重复基因的周转也会发生。影响重复的分子过程意味着，一个重复的DNA家族越古老，它就越有可能以不同的形式存在，并在一个物种的许多地方存在。支持这一假设的例子来自鳞甲属。
Most higher plant genomes contain a high proportion of repeated sequences. Thus repetitive DNA is a major contributor to plant chromosome structure. The variation in total DNA content between species is due mostly to variation in repeated DNA content. Some repeats of the same family are arranged in tandem arrays, at the sites of heterochromatin. Examples from theSecalegenus are described. Arrays of the same sequence are often present at many chromosomal sites. Heterochromatin often contains arrays of several unrelated sequences. The evolution of such arrays in populations is discussed. Other repeats are dispersed at many locations in the chromosomes. Many are likely to be or have evolved from transposable elements. The structures of some plant transposable elements, in particular the sequences of the terminal inverted repeats, are described. Some elements in soybean, antirrhinum and maize have the same inverted terminal repeat sequences. Other elements of maize and wheat share terminal homology with elements from yeast,Drosophila, man and mouse. The evolution of transposable elements in plant populations is discussed. The amplification, deletion and transposition of different repeated DNA sequences and the spread of the mutations in populations produces a turnover of repetitive DNA during evolution. This turnover process and the molecular mechanisms involved are discussed and shown to be responsible for divergence of chromosome structure between species. Turnover of repeated genes also occurs. The molecular processes affecting repeats imply that the older a repetitive DNA family the more likely it is to exist in different forms and in many locations within a species. Examples to support this hypothesis are provided from the Secale genus.