一个由法国、美国、澳大利亚等国科学家组成的研究小组日前为小麦的一个基因组绘制出了首幅物理图谱，这一成果将有助于科学家培育出更高产和抗旱的小麦新品种。
基因组物理图谱是指有关构成基因组的全部基因的排列和间距的信息，它是通过对构成基因组的DNA分子进行测定而绘制的。绘制物理图谱的目的是把有关基因的遗传信息及其在每条染色体上的相对位置线性而系统地排列出来。
这项研究由法国国家农艺研究所专家克莱蒙·费朗牵头完成。据介绍，小麦的基因组不但数量多，且结构复杂，因此对其进行测序被视为“不可能完成的任务”。小麦的染色体共含有170亿对碱基，是水稻的约40倍，是人体的约5倍，因此测序工作进展相对缓慢。
研究人员介绍说，绘制基因组物理图谱是为基因组测序的基础，所以他们从小麦最大的染色体3B入手。这条染色体含有10亿对碱基和1036个基因重叠组，科学家们通过对基因进行标记，成功地将其排列顺序，并绘出了物理图谱。
研究人员表示，物理图谱能帮助人们迅速锁定控制小麦产量和数量的基因，从而对作物的品种进行改良。科学家们已根据该图谱确定了一个抗黑锈病基因的具体位置。黑锈病会严重影响小麦产量，如能培育出抗该病的新品种，将有望大幅提高小麦产量。
这一研究成果已发表在10月3日出版的美国《科学》（Science）杂志上。（生物谷Bioon.com）
生物谷推荐原始出处：
Science，Vol. 322. no. 5898, pp. 101 - 104，Etienne Paux，Catherine Feuillet
A Physical Map of the 1-Gigabase Bread Wheat Chromosome 3B
Etienne Paux,1 Pierre Sourdille,1 Jérôme Salse,1 Cyrille Saintenac,1 Frédéric Choulet,1 Philippe Leroy,1Abraham Korol,2 Monika Michalak,3 Shahryar Kianian,3 Wolfgang Spielmeyer,4 Evans Lagudah,4Daryl Somers,5 Andrzej Kilian,6 Michael Alaux,7 Sonia Vautrin,8 Hélène Bergès,8 Kellye Eversole,9Rudi Appels,10 Jan Safar,11 Hana Simkova,11 Jaroslav Dolezel,11 Michel Bernard,1 Catherine Feuillet1
As the staple food for 35% of the world's population, wheat is one of the most important crop species. To date, sequence-based tools to accelerate wheat improvement are lacking. As part of the international effort to sequence the 17–billion–base-pair hexaploid bread wheat genome (2n = 6x = 42 chromosomes), we constructed a bacterial artificial chromosome (BAC)–based integrated physical map of the largest chromosome, 3B, that alone is 995 megabases. A chromosome-specific BAC library was used to assemble 82% of the chromosome into 1036 contigs that were anchored with 1443 molecular markers, providing a major resource for genetic and genomic studies. This physical map establishes a template for the remaining wheat chromosomes and demonstrates the feasibility of constructing physical maps in large, complex, polyploid genomes with a chromosome-based approach.
1 Institut National de la Recherche Agronomique, Université Blaise Pascal (INRA-UBP), UMR 1095, Genetics Diversity and Ecophysiology of Cereals, Clermont-Ferrand, France.
2 Institute of Evolution, University of Haifa, Haifa, Israel.
3 Department of Plant Sciences, North Dakota State University, Fargo, ND, USA.
4 Commonwealth Scientific and Industrial Research Organization Plant Industry, Canberra, Australia.
5 Agriculture and Agri-Food Canada, Cereal Research Centre, Winnipeg, Canada.
6 Diversity Arrays Technology, Yarralumla, Canberra, Australia.
7 INRA–Unité de Recherches en Génomique-Info, Versailles, France.
8 INRA–Centre National de Ressources Génomiques Végétales, Toulouse, France.
9 International Wheat Genome Sequencing Consortium, Eversole Associates, Bethesda, MD, USA.
10 Centre for Comparative Genomics, Murdoch University, Perth, Australia.
11 Laboratory of Molecular Cytogenetics and Cytometry, Institute of Experimental Botany, Olomouc, Czech Republic.
