【The Plant Cell】开发出破译复杂谷物基因组的方法
The Plant Cell：开发出破译复杂谷物基因组的方法
2012/02/07 16:57:53
德国莱布尼茨植物遗传学与农作物研究所的Stein博士带领一个国际科研团体，经过两年努力，终于首次观察到谷类作物大麦的全基因组。科学家们借助他们建立的新方法，已能确定大麦全部基因2/3的排序，这些成果成为完整破译大麦与相近的小麦基因组的基础。
根据来自世界粮农组织的信息，小麦与大麦在全球种植最多的谷物排名中分别占据第一和第五位，它们对于经济与科研具有重要意义。科学家们只有在掌握了植物的遗传密码后，才能理解为其复杂性状负责的分子机制。而了解遗传密码也是改善作物重要性能的基础，比如耐旱与抵抗力。
然而谷物基因组极其庞大且构造复杂，这使得完整解码困难很大。Stein博士称，大麦基因组约为人类基因组的两倍半，是水稻基因组的12倍，全部解码需要1亿美元经费。成功测试的新方法现已用来研究更为庞大的小麦基因组。
由于很多农作物具有相似性，研究人员可以将大麦的遗传信息与特征表现之间的关系转用于研究比如黑麦等其他近似的谷类。
Frequent Gene Movement and Pseudogene Evolution Is Common to the Large and Complex Genomes of Wheat, Barley, and Their Relatives
The Plant Cell doi: 10.1105/tpc.111.086629
Thomas Wicker, Klaus F.X. Mayer, Heidrun Gundlach, Mihaela Martis, Burkhard Steuernagel, Uwe Scholz, Hana imkovád, Marie Kubaláková, Frédéric Choulet, Stefan Taudien, Matthias Platzer, Catherine Feuillet, Tzion Fahima, Hikmet Budak, Jaroslav Dole?el, Beat Keller and Nils Stein
All six arms of the group 1 chromosomes of hexaploid wheat (Triticum aestivum) were sequenced with Roche/454 to 1.3- to 2.2-fold coverage and compared with similar data sets from the homoeologous chromosome 1H of barley (Hordeum vulgare). Six to ten thousand gene sequences were sampled per chromosome. These were classified into genes that have their closest homologs in the Triticeae group 1 syntenic region in Brachypodium, rice (Oryza sativa), and/or sorghum (Sorghum bicolor) and genes that have their homologs elsewhere in these model grass genomes. Although the number of syntenic genes was similar between the homologous groups, the amount of nonsyntenic genes was found to be extremely diverse between wheat and barley and even between wheat subgenomes. Besides a small core group of genes that are nonsyntenic in other grasses but conserved among Triticeae, we found thousands of genic sequences that are specific to chromosomes of one single species or subgenome. By examining in detail 50 genes from chromosome 1H for which BAC sequences were available, we found that many represent pseudogenes that resulted from transposable element activity and double-strand break repair. Thus, Triticeae seem to accumulate nonsyntenic genes frequently. Since many of them are likely to be pseudogenes, total gene numbers in Triticeae are prone to pronounced overestimates.