2008-05-14
开启生物体之间差别原因可能之锁
一直以为基因数决定了生物体之间的巨大差别。可最近发表于PNAS的一项研究表明，人类和果蝇等简单有机体的巨大差别不在于基因数，而在于他们体内蛋白质相互作用的数量。蛋白质相互作用应该是一把开启生物体之间差别程度原因之锁的钥匙。
在该研究中，英国伦敦帝国理工学院生命科学系的Michael Stumpf 和同事设计了一种新颖的数学工具，结合相关数据能够估计出一个有机体蛋白质相互作用网络的尺寸。结果显示，人体内蛋白质相互作用的数量大约为65万，是果蝇的10倍，是单细胞酵母等的20倍。这与之前基因数的比较结果相差巨大-人类的基因数大约为24000，果蝇的大约为14000，二者相差不到2倍。
Stumpf 表示，”科学家一度认为，有机体体内蛋白质相互作用的复杂性决定了他的生物学复杂性。但是因为鉴别和描绘这些相互作用的研究并不多，所以迄今尚无法估算出一个有机体内蛋白质相互作用网络的尺寸，也无法与其它有机体进行比较。”
下一步，研究人员计划根据物种间的仔细比较结果来做出更加详细的估计。这对理解某些现象至关重要，比如，为什么面包酵母对于面包和啤酒的生产很重要，而有些与它进化关系很近的种类却会导致高致死率的真菌感染。
PS：研究人员将人体内蛋白质相互作用的总数称作”人类相互作用组”（human interactome），意在与人类基因组相比较。
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Estimating the size of the human interactome 3 F% G4 e) _” s
Michael P. H. Stumpf,Thomas Thorne, Eric de Silva, Ronald Stewart, Hyeong Jun An, Michael Lappe, and Carsten Wiuf; b% e’ W% K1 i$ g) d2 }* Y
Division of Molecular Biosciences, Imperial College London, Wolfson Building, London SW7 2AZ, United Kingdom; Institute of Mathematical Sciences, Imperial College London, London SW7 2AZ, United Kingdom; ||Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany; and Bioinformatics Research Center, University of Aarhus, 8000 Aarhus C, Denmark 6 w+ o: O0 O& ]# a
Edited by Burton H. Singer, Princeton University, Princeton, NJ, and approved February 19, 2008 (received for review August 27, 2007)
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After the completion of the human and other genome projects it emerged that the number of genes in organisms as diverse as fruit flies, nematodes, and humans does not reflect our perception of their relative complexity. Here, we provide reliable evidence that the size of protein interaction networks in different organisms appears to correlate much better with their apparent biological complexity. We develop a stable and powerful, yet simple, statistical procedure to estimate the size of the whole network from subnet data. This approach is then applied to a range of eukaryotic organisms for which extensive protein interaction data have been collected and we estimate the number of interactions in humans to be 650,000. We find that the human interaction network is one order of magnitude bigger than the Drosophila melanogaster interactome and 3 times bigger than in Caenorhabditis elegans.
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