Comparative fluorescence in situ hybridization mapping of a 431-kb Arabidopsis thaliana bacterial artificial chromosome contig reveals the role of chromosomal duplications in the expansion of the Brassica rapa genome.
Comparative fluorescence in situ hybridization mapping of a 431-kb Arabidopsis thaliana bacterial artificial chromosome contig reveals the role of chromosomal duplications in the expansion of the Brassica rapa genome.
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DOI：
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发表时间：
2000-10
期刊：
影响因子：
3.3
通讯作者：
S. Jackson;Z. Cheng;M. Wang;H. Goodman;J. Jiang
中科院分区：
文献类型：
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作者：
S. Jackson;Z. Cheng;M. Wang;H. Goodman;J. Jiang
比较基因组研究是我们理解基因组进化的重要贡献者。大多数植物基因组比较研究都是基于不同基因组中同源DNA位点的遗传作图。由于缺乏有效和负担得起的技术，大规模比较物理制图一直受到阻碍。我们在这里报道了荧光原位杂交（FISH）技术在拟南芥和油菜之间的比较物理定位的适应性。在拟南拟南（A. thaliana） 2号染色体431 kb的连续区域内，分别在拟南拟南（B. rapa）染色体和DNA纤维上定位了6条细菌人工染色体（BACs）。该DNA片段在拟南芥基因组中只有一个位置，但与4到6条rapa染色体杂交，表明rapa基因组中存在多重复制。来自相同BACs的纤维- fish信号的大小在rapa中并不比在拟南芥中长，这表明该基因组区域在rapa基因组中是重复的而不是扩展的。比较纤维- fish定位结果支持染色体复制，而不是由于重复序列在基因间区域积累而产生的区域扩张，在rapa基因组的进化中发挥了主要作用。
Comparative genome studies are important contributors to our understanding of genome evolution. Most comparative genome studies in plants have been based on genetic mapping of homologous DNA loci in different genomes. Large-scale comparative physical mapping has been hindered by the lack of efficient and affordable techniques. We report here the adaptation of fluorescence in situ hybridization (FISH) techniques for comparative physical mapping between Arabidopsis thaliana and Brassica rapa. A set of six bacterial artificial chromosomes (BACs) representing a 431-kb contiguous region of chromosome 2 of A. thaliana was mapped on both chromosomes and DNA fibers of B. rapa. This DNA fragment has a single location in the A. thaliana genome, but hybridized to four to six B. rapa chromosomes, indicating multiple duplications in the B. rapa genome. The sizes of the fiber-FISH signals from the same BACs were not longer in B. rapa than those in A. thaliana, suggesting that this genomic region is duplicated but not expanded in the B. rapa genome. The comparative fiber-FISH mapping results support that chromosomal duplications, rather than regional expansion due to accumulation of repetitive sequences in the intergenic regions, played the major role in the evolution of the B. rapa genome.