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Biotech Science

Synthetic Genome Drives Bacterial Cell 174

Dr. Eggman writes "Physorg.com brings us news of a synthetic genome, produced by the J. Craig Venter Institute, being used in an existing bacterial cell for the first time. Using a combination of biological hosts, the technique produces short strings of DNA by machine which are then inserted into yeast to be stitched together via DNA-repair enzymes. The medium sequences are passed into E. coli and back into yeast. After three rounds, a genome of three million base pairs was produced." (More below.)
"Specifically, the genome of M. mycoides was synthesized from scratch. This synthetic genome was then inserted into the cells of a bacteria known as Mycoplasm capricolum. The result is a cell, driven by a synthetic genome, producing not the proteins of Mycoplasm capricolum, but of M. mycoides. The institute has far-reaching plans for its synthetic life program, including designing algae that can capture carbon dioxide, make new hydrocarbons for refineries, make new chemicals or food ingredients, and speed up vaccine production." The BBC has coverage of the hybrid cell as well.
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Synthetic Genome Drives Bacterial Cell

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  • by ArbitraryDescriptor ( 1257752 ) on Thursday May 20, 2010 @04:32PM (#32284826)
    Article is unclear on this.

    Because current machines can only assemble relatively short strings of DNA letters at a time, the researchers inserted the shorter sequences into yeast, whose DNA-repair enzymes linked the strings together. They then transferred the medium-sized strings into E. coli and back into yeast. After three rounds of assembly, the researchers had produced a genome over a million base pairs long.

    I read this as:

    Sequencer-> Yeast -> E. coli -> Yeast -> Repeat
    Short segments-> Merged segment -> ? -> ??? -> Full M. mycoides Genome

  • by ArbitraryDescriptor ( 1257752 ) on Thursday May 20, 2010 @05:32PM (#32285804)
    Ah, thanks for that. From the PDF:

    1. The JCVI team designed specific cassettes of DNA that were 1,080 base pairs long with overlaps of 80 base pairs (bp) at their ends to aid in building the longer stretches of DNA. These were made according to JCVI’s specifications by the DNA synthesis company, Blue Heron Biotechnology.

    2. Then the team employed a three stage process using yeast to build the genome using 1,078 cassettes that are 1,080 bp in length. The first stage involves taking 10 cassettes of DNA at a time to build 10,000 bp long segments. In the second stage, these 10,000 bp segments are taken 10 at a time to produce eleven 100,000 bp long segments. Finally, all 11 segments are assembled into a complete synthetic genome as an extra chromosome in a

    yeast cell, by using yeast genetic systems. 3. The complete synthetic M. mycoides genome is then released from the yeast cell and transplanted into M. capricolum recipient cells that have had the gene for a restriction enzyme removed. Following incubation, viable M. mycoides cells are produced in which the only DNA present is the synthetic genome. These cells are controlled only by that synthetic genome.

    Which then makes sense of the chart which states the sequence as:

    1. Oligonucleotide Synthesizer
    2. Yeast
    3. ?
    4. Extract Complete Genome from Yeast

    1. Oligonucleotides in 1,080 bp cassettes (1,078)

    2. 10,080 bp assemblies (109)
    (Assemble 11X)

    3. 100,000 bp assemblies (11)
    (Assemble 1X)

    4. 1,077,947 bp

    So I guess the ?? in step 3 is the E. coli, which assembles the 10,000bp segments into 100,000 bp segments, which are finally stitched together back in the yeast as an extra genome.

  • by HeckRuler ( 1369601 ) on Thursday May 20, 2010 @05:33PM (#32285810)

    If you go to Indiana you don't see the Monsanto soybeans growing wild in a ditch.

    That's because Monsanto seeds are sterile. You can't simply buy once and plant some of the seeds from that crop, you have to buy from Monsanto each year. Seriously, this is basic bio-tech information from the 90's.

  • Completely false. (Score:3, Informative)

    by base_chakra ( 230686 ) on Thursday May 20, 2010 @11:11PM (#32288754)

    This article [monsanto.com] on monsanto.com makes it very plain:

    "Monsanto has never developed or commercialized a sterile seed product. Sharing many of the concerns of small landholder farmers, Monsanto made a commitment in 1999 not to commercialize sterile seed technology in food crops. We stand firmly by this commitment. We have no plans or research that would violate this commitment in any way."

    In spite of this reassurance, one can't rule out the possibility that Monsanto will decide later that it's in their own best interest to market a sterile seed technology.

    Monsanto has persecuted many farmers for allegedly saving the seeds of their GM plants (corn, soybeans, and cotton) for planting. See http://www.monsanto.com/seedpatentprotection/monsantos_position.asp [monsanto.com] for one of the several Monsanto resources that discusses this practice. There's very little a farmer can do to protect his business when Monsanto makes such an accusation. The legal battles can last years, and are devastating.

Truth is free, but information costs.