Triticeae Genome Structure and Evolution
Triticeae Genome Structure and Evolution
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DOI：
10.1007/978-0-387-77489-3_23
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发表时间：
2009-01-01
期刊：
影响因子：
--
通讯作者：
Dvorak, Jan
中科院分区：
文献类型：
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作者：
Dvorak, Jan
重复核苷酸序列是小麦族基因组的最大组成部分，约占核DNA的90%。串联重复序列在染色体有丝分裂和减数分裂过程中起着重要的作用。散布的重复序列填充基因间区域。这一组成部分最显著的属性是其前所未有的周转速度，这与基因含量的稳定性形成鲜明对比。“基因秩序悖论”这个术语是为了反映蒂尔斯的二分法而创造的。提出了一个模型，假设存在两个层次的小麦族基因组，“保守”和“动态”来解释这一悖论及其进化原因。小麦族基因组中基因含量的许多方面，如单拷贝基因的定位、多基因位点、基因缺失和重复、基因密度、限制性片段长度多态性和单核苷酸多态性、新基因和谱系特异基因的定位以及同线性水平，都与着丝粒-端粒轴上的重组率和基因定位有关。特别注意的是，沿沿着染色体的基因分布的讨论。有人指出，存在基因丰富的岛屿的证据是薄弱的。提出了一个基因密度与重组率相关的模型。这表明小麦族基因组中大量的重复序列在新基因的进化和适应中起着一定的作用。
Repeated nucleotide sequences are by far the largest component of Triticeae genomes, accounting for about 90% of the nuclear DNA. Tandem repeated sequences play all important role in chromosome function during mitosis and meiosis. Interspersed repeated sequences fill the intergenic, regions. The most remarkable attribute of this component is its unprecedented rate of turnover, which is in stark contrast to the stability of gene content. The term "gene order paradox" is coined to reflect tills dichotomy. A model is proposed postulating the existence of two strata in Triticeae genomes, "conservative" and "dynamic" to account for this paradox and its evolutionary causes. Numerous aspects of gene content in Triticeae genomes, Such as the location of single-copy genes, multi-gene loci, gene deletions and duplications, gene density, restriction fragment length polymorphism and single nucleotide polymorphism, location of novel and lineage-specific genes, and the level of synteny, correlate with recombination rate and gene location oil the centromere-telomere axis. Special attention is devoted to the discussion of gene distribution along chromosomes. It is pointed out that evidence for the existence of gene-rich islands is weak. A model accounting for correlation between gene density and recombination rate is proposed. It is suggested that the vast amounts of repeated sequences in Triticeae genomes play a role in the evolution of new genes and in adaptation.