A highly conserved gene island of three genes on chromosome 3B of hexaploid wheat: diverse gene function and genomic structure maintained in a tightly linked block
A highly conserved gene island of three genes on chromosome 3B of hexaploid wheat: diverse gene function and genomic structure maintained in a tightly linked block
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DOI：
10.1186/1471-2229-10-98
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发表时间：
2010-05-27
影响因子：
5.3
通讯作者：
Bellgard, Matthew
中科院分区：
文献类型：
--
作者：
Breen, James;Wicker, Thomas;Bellgard, Matthew
背景：小麦基因组的复杂性是由一波又一波的反转录转座子插入引起的。小麦中重复元素的快速替换所产生的基因缺失和中断导致了谷类之间微小(亚兆基)水平的共线性中断。考虑到在给定的时间跨度内可能发生的基因组变化，物种之间的基因保护往往意味着重要的功能或区域限制，不允许基因组结构的变化。本文所完成的ctg1034重叠群的初步研究是因为它属于Sr2抗性基因座区域，但随后详细的作图研究将其定位在3B的长臂上，并揭示了它的异常特征。中国春)基因组被用来组装来自染色体3B物理图谱FPC重叠群ctg1034的15个小麦BAC，形成一个785,553bp的基因组序列。该ctg1034序列被注释为生物学特征，例如基因和转座元件。在>；80%的重复DNA序列中鉴定出一个三基因岛。利用生物信息学分析，它们的基因功能没有明显的相似之处。Ctg1034基因岛也显示出完全保守的基因顺序和方向，与在已公开的玉米、水稻、高粱和玉米基因组序列中发现的同线基因岛一样，尽管基因间隙和内含子是不同的。结论：ctg1034位于缺失bin 3BL7的异色C带区域内，基于异色串联重复序列的鉴定和含有Gypsy LTR逆转座子的显色域的显著匹配。我们还推测，在其他高度重复的序列中，这个位置可能解释了基因岛内基因顺序和方向相对稳定的原因。本文中的序列数据已保存在GenBank数据库中，登录号为：GQ422824
Background: The complexity of the wheat genome has resulted from waves of retrotransposable element insertions. Gene deletions and disruptions generated by the fast replacement of repetitive elements in wheat have resulted in disruption of colinearity at a micro (sub-megabase) level among the cereals. In view of genomic changes that are possible within a given time span, conservation of genes between species tends to imply an important functional or regional constraint that does not permit a change in genomic structure. The ctg1034 contig completed in this paper was initially studied because it was assigned to the Sr2 resistance locus region, but detailed mapping studies subsequently assigned it to the long arm of 3B and revealed its unusual features.Results: BAC shotgun sequencing of the hexaploid wheat (Triticum aestivum cv. Chinese Spring) genome has been used to assemble a group of 15 wheat BACs from the chromosome 3B physical map FPC contig ctg1034 into a 783,553 bp genomic sequence. This ctg1034 sequence was annotated for biological features such as genes and transposable elements. A three-gene island was identified among >80% repetitive DNA sequence. Using bioinformatics analysis there were no observable similarity in their gene functions. The ctg1034 gene island also displayed complete conservation of gene order and orientation with syntenic gene islands found in publicly available genome sequences of Brachypodium distachyon, Oryza sativa, Sorghum bicolor and Zea mays, even though the intergenic space and introns were divergent.Conclusion: We propose that ctg1034 is located within the heterochromatic C-band region of deletion bin 3BL7 based on the identification of heterochromatic tandem repeats and presence of significant matches to chromodomaincontaining gypsy LTR retrotransposable elements. We also speculate that this location, among other highly repetitive sequences, may account for the relative stability in gene order and orientation within the gene island. Sequence data from this article have been deposited with the GenBank Data Libraries under accession no. GQ422824