‘开云|kaiyun’美科学家合成出迄今最简单生命形式

US scientists have stripped life back to its bare essentials — creating a synthetic microbe with the absolute minimum genetic information needed to grow and reproduce. 美国科学家将生命的多余部分去除，只留给最基本的要素，由此建构出有一种制备微生物，这种制备微生物享有生长和交配所需的低于限度的基因信息。The researchers, led by Craig Venter, the genomics pioneer, made Syn3.0, the “minimal synthetic bacterial cell”, as a follow-up to their much publicised creation in 2010 of Syn1.0, the first living cell with DNA (its genome) made from scratch using laboratory chemicals. 由基因学先驱克雷格文特尔(Craig Venter)领导的研究人员建构了取名为Syn3.0的“最小化制备细菌细胞”，这是他们在2010年建构的曾获得普遍宣传的Syn1.0的先前成果。

Syn1.0是首个享有用实验室化学品从零制备出有的脱氧核糖核酸(DNA)的活细胞。They hope Syn3.0 or its successors will provide a platform to which synthetic biologists can add genes for particular purposes, such as producing drugs or biofuels, though the more immediate aim is to understand better the fundamental biochemistry of life. 研究人员期望，Syn3.0或其先前样品能获取一个平台，可供制备生物学家重新加入有特定用途的基因，比如生产药品或生物燃料的基因，尽管Syn3.0更加必要的目标是更佳地解读生命的基本生化机理。The project, published in the journal Science, took four years longer than expected, Dr Venter said, and revealed “surprising” gaps in biological knowledge. 这个项目的研究成果公开发表在《科学》(Science)期刊上。

文特尔博士回应，该项目持续的时间比预期宽了四年，说明了出有生物学科学知识中不存在“令人吃惊的”空白。The initial approach was to design a minimal bacterial genome using all the information available from the scientific literature, but that failed. The failure shows that “our current knowledge of biology is not sufficient to sit down and design a living organism and build it”, he said. 这个研究团队最初的思路是利用科学文献中获取的所有信息，设计一种最小化的细菌基因组，但这条路没回头通。文特尔博士说道，这次告终证明“我们目前的生物学科学知识，足以让我们椅子来设计一个活的有机体并将它其实”。Instead, the team went back to Syn3.0, which was based on Mycoplasma mycoides, the naturally occurring bacterium, and began the long process of discovering which of its 901 genes were essential for life by finding out what happened when each one was deleted. 后来，该团队调整了思路，转而研发基于丝状支原体的Syn3.0。

该团队进行了漫长的探寻，通过逐一去除再行仔细观察结果的办法，仔细观察丝状支原体的901个基因中有哪些是必不可少的。丝状支原体是一种天然的细菌。

One by one the unnecessary genes were eliminated until the team, working in California at the J Craig Venter Institute and Synthetic Genomics, its associated company, was left with 473 genes essential for replication and growth. 就这样，不必要的基因被一个相接一个地去除，最后获得了473个拷贝和生长所必须的基因。该团队的研究工作是在美国加州约翰克雷格文特尔研究所(J. Craig Venter Institute)及其附属公司制备基因组学(Synthetic Genomics)进行的。The DNA encoding these 473 genes, amounting to 531,000 chemical “letters” of genetic code, was then synthesised in the lab and the resulting synthetic genome transplanted into the shell of M capriolum, another bacterium whose own DNA had been removed. 编码构成这473个基因的DNA，相等于53.1万个基因代码化学“字母”。

这些DNA随后在实验室中被制备出来，制备出有的基因组被植入另一种细菌山羊支原体(M capricolum)的壳中，该支原体自身的DNA已被去除。The synthetic genome took over the biological machinery of the host cell, producing a healthy bacterium that reproduces rapidly in lab cultures and doubles its colony size every three hours. 该制备基因组接管了宿主细胞的生物学运作，产生了一种强壮的细菌，该细菌经实验室培育可很快交配，菌落规模每三小时翻一番。

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