英国桑格研究所16日发布新闻公报说，他们发明一种快速高效分析细菌基因组中成千上万个基因的新技术，可以在一次实验中识别出“有用”的基因，从而防治细菌导致的疾病。这种名为TraDIS技术的实质是在基因层面上的“剪切和粘贴”。基因是DNA链上具有特定功能的一个片段，如果将这个片段中一些地方“剪切”掉，再“粘贴”上一段抑制其功能的物质，那么这个基因就会失去作用。
如研究人员对伤寒沙门氏菌的每个基因都进行了“剪切和粘贴”处理，得到约100万个发生了不同基因变化的细菌，随后，将它们一起培养。那些因为基因变化而功能受损的细菌不会生长，于是在一次实验中识别出了“有用”基因。结果显示，维持伤寒沙门氏菌基本生存的“有用”基因只有356个，其他数千个基因则不是必不可少的。
研究人员称，这一技术有助于医疗研究。比如伤寒沙门氏菌常存在于携带者的胆囊中，并由此传染他人，但这一传染途径的前提是细菌对胆汁要有抵抗能力。研究人员利用TraDIS技术在胆汁中培养细菌，最终确定了169个与抵抗胆汁能力有关的基因。在此基础上研发治疗手段，可以帮助防治伤寒沙门氏菌造成的疾病。
相关研究报告发表在美国新一期《基因组研究》杂志上。（生物谷Bioon.com）
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Genome Research October 13, 2009, doi:10.1101/gr.097097.109
Simultaneous assay of every Salmonella Typhi gene using one million transposon mutants
Gemma C. Langridge1,6, Minh-Duy Phan1,6, Daniel J. Turner1,6, Timothy T. Perkins1, Leopold Parts1, Jana Haase2, Ian Charles3, Duncan J. Maskell4, Sarah E. Peters4, Gordon Dougan1, John Wain5, Julian Parkhill1,7 and A. Keith Turner1
1The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom;
2Environmental Research Institute, University College, Cork, Ireland;
3Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom;
4Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, United Kingdom;
5Laboratory of Gastrointestinal Pathogens, Centre for Infections, Health Protection Agency, Colindale, London NW9 5HT, United Kingdom
Very high-throughput sequencing technologies need to be matched by high-throughput functional studies if we are to make full use of the current explosion in genome sequences. We have generated a very large bacterial mutant pool, consisting of an estimated 1.1 million transposon mutants and we have used genomic DNA from this mutant pool, and Illumina nucleotide sequencing to prime from the transposon and sequence into the adjacent target DNA. With this method, which we have called TraDIS (transposon directed insertion-site sequencing), we have been able to map 370,000 unique transposon insertion sites to the Salmonella enterica serovar Typhi chromosome. The unprecedented density and resolution of mapped insertion sites, an average of one every 13 base pairs, has allowed us to assay simultaneously every gene in the genome for essentiality and generate a genome-wide list of candidate essential genes. In addition, the semiquantitative nature of the assay allowed us to identify genes that are advantageous and those that are disadvantageous for growth under standard laboratory conditions. Comparison of the mutant pool following growth in the presence or absence of ox bile enabled every gene to be assayed for its contribution toward bile tolerance, a trait required of any enteric bacterium and for carriage of S. Typhi in the gall bladder. This screen validated our hypothesis that we can simultaneously assay every gene in the genome to identify niche-specific essential genes.
