[轉錄][爆卦] 人造細菌,創造出新的生命!!
※ [本文轉錄自 nfsong 信箱]
作者: dearevan (歸去，也無風雨也無晴) 看板: Gossiping
標題: [爆卦] 人造細菌,創造出新的生命!!
時間: Fri May 21 02:43:40 2010
剛剛隔壁實驗室的學長跑來串門子閒聊學術上的事情
他突然提到今天在Science的網站上看到一篇很有趣的文章
Daniel G. Gibson 與J. Craig Venter
完全只利用基本化學物質材料, 合成打造出一種細菌
就某種意義上來說, 等於是人造生命的開端
這消息真的蠻讓人震驚的
那學長還很失落說他本來想當第一個做出人造生命的人
以下是science網站的新聞稿 以及原始文獻出處
http://www.sciencemag.org/cgi/content/abstract/science.1190719
(原始文獻)
http://www.sciencemag.org/cgi/content/full/328/5981/958/F1
(合成細菌的電顯照片)
http://www.sciencemag.org/cgi/content/full/328/5981/958
(新聞稿)
NEWS OF THE WEEK
GENOMICS:
Synthetic Genome Brings New Life to Bacterium
Elizabeth Pennisi
For 15 years, J. Craig Venter has chased a dream: to build a genome from
scratch and use it to make synthetic life. Now, he and his team at the J.
Craig Venter Institute (JCVI) in Rockville, Maryland, and San Diego,
California, say they have realized that dream. In this week's Science Express
(www.sciencemag.org/cgi/content/abstract/science.1190719), they describe the
stepwise creation of a bacterial chromosome and the successful transfer of it
into a bacterium, where it replaced the native DNA. Powered by the synthetic
genome, that microbial cell began replicating and making a new set of protein
This is "a defining moment in the history of biology and biotechnology," says
Mark Bedau, a philosopher at Reed College in Portland, Oregon, and editor of
the scientific journal Artificial Life. "It represents an important technical
milestone in the new field of synthetic genomics," says yeast biologist Jef
Boeke of Johns Hopkins University School of Medicine in Baltimore, Maryland.
The synthetic genome created by Venter's team is almost identical to that of
a natural bacterium. It was achieved at great expense, an estimated $40
million, and effort, 20 people working for more than a decade. Despite this
success, creating heavily customized genomes, such as ones that make fuels or
pharmaceuticals, and getting them to "boot" up the same way in a cell is not
yet a reality. "There are great challenges ahead before genetic engineers can
mix, match, and fully design an organism's genome from scratch," notes Paul
Keim, a molecular geneticist at Northern Arizona University in Flagstaff.
The "synthetic" bacteria unveiled this week have their origins in a project
headed by Venter and JCVI colleagues Clyde Hutchison III and Hamilton Smith
to determine the minimal instructions needed for microbial life and from
there add genes that could turn a bacterium into a factory producing
compounds useful for humankind. In 1995, a team led by the trio sequenced the
600,000-base chromosome of a bacterium called Mycoplasma genitalium, the
smallest genome of a free-living organism. The microbe has about 500 genes,
and researchers found they could delete 100 individual genes without ill
effect (Science, 14 February 2003, p. 1006).
But confirming the minimal genome suggested by those experiments required
synthesizing a full bacterial chromosome and getting it to work in a
recipient cell, two steps that have taken years because the technology to
make and manipulate whole chromosomes did not exist. In 2007, Venter, Smith,
Hutchison, and colleagues finally demonstrated that they could transplant
natural chromosomes from one microbial species to another (Science, 3 August
2007, p. 632). By 2008, they showed that they could make an artificial
chromosome that matched M. genitalium's but also contained "watermark" DNA
sequences that would enable them to tell the synthetic genome from the
natural one (Science, 29 February 2008, p. 1215).
But combining those steps became bogged down, in part because M. genitalium
grows so slowly that one experiment can take weeks to complete. The team
decided to change microbes in midstream, sequencing the 1-million-base genome
of the faster-growing M. mycoides and beginning to build a synthetic copy of
its chromosome. Last year, they showed they could extract the M. mycoides
natural chromosome, place it into yeast, modify the bacterial genome, and
then transfer it to M. capricolum, a close microbial relative (Science, 21
August 2009, p. 928; 25 September 2009, p. 1693). The next step was to show
that the synthetic copy of the bacterial DNA could be handled the same way.
The researchers started building their synthetic chromosome by going DNA
shopping. They bought from a company more than 1000 1080-base sequences that
covered the whole M. mycoides genome; to facilitate their assembly in the
correct order, the ends of each sequence had 80 bases that overlapped with
its neighbors. So that the assembled genome would be recognizable as
synthetic, four of the ordered DNA sequences contained strings of bases that,
in code, spell out an e-mail address, the names of many of the people
involved in the project, and a few famous quotations.
Using yeast to assemble the synthetic DNA in stages, the researchers first
stitched together 10,000-base sequences, then 100,000-base sequences, and
finally the complete genome. However, when they initially put the synthetic
genome into M. capricolum, nothing happened. Like computer programmers
debugging faulty software, they systematically transplanted combinations of
synthetic and natural DNA, finally homing in on a single-base mistake in the
synthetic genome. The error delayed the project 3 months.
After months of unsuccessfully transplanting these various genome
combinations, the team's fortune changed about a month ago when the
biologists found a blue colony of bacteria had rapidly grown on a lab plate
over the weekend. (Blue showed the cells were using the new genome). Project
leader Daniel Gibson sent Venter a text message declaring success. "I took my
video camera in and filmed [the plate]," says Venter.
They sequenced the DNA in this colony, confirming that the bacteria had the
synthetic genome, and checked that the microbes were indeed making proteins
characteristic of M. mycoides rather than M capricolum. The colony grew like
a typical M. mycoides as well. "We clearly transformed one cell into
another," says Venter.
"That's a pretty amazing accomplishment," says Anthony Forster, a molecular
biologist at Vanderbilt University in Nashville, Tennessee. Still, he and
others emphasize that this work didn't create a truly synthetic life form,
because the genome was put into an existing cell.
At the moment, the techniques employed by Venter's team are too difficult to
appeal to any potential bioterrorists, researchers stress. Nonetheless, "this
experiment will certainly reconfigure the ethical imagination," says Paul
Rabinow, an anthropologist at the University of California, Berkeley, who
studies synthetic biology. "Over the long term, the approach will be used to
synthesize increasingly novel designed genomes," says Kenneth Oye, a social
scientist at the Massachusetts Institute of Technology in Cambridge. "Right
now, we are shooting in the dark as to what the long-term benefits and
long-term risks will be."
As ever more "artificial" life comes into reach, regulatory agencies will
need to establish the proper regulations in a timely fashion, adds Oye. "The
possibility of misuse unfortunately exists," says Eckard Wimmer of Stony
Brook University in New York state, who led a team that in 2002 created the
first synthetic virus (Science, 9 August 2002, p. 1016).
Venter says that JCVI has applied for several patents covering the work,
assigning them to his company, Synthetic Genomics, which provided much of the
funding for the project. A technology watchdog group, ETC Group in Ottawa,
has argued that these actions could result in a monopoly on synthesized life
(Science, 15 June 2007, p. 1557), but others are not worried. Given the
current climate for granting and upholding patents of this type, says Oye,
"it is unlikely that Synthetic Genomics will become the Microsoft of
synthetic biology."
"One thing is sure," Boeke says. "Interesting creatures will be bubbling out
of the Venter Institute's labs."
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