Being able to design and - artificially - create entire genomes, instead of just short lengths of DNA, will dramatically speed up the process of engineering microbes that can carry out tasks such as efficiently producing biofuels or vaccines.
Until last year, biologists hadn't been able to make large enough pieces of DNA to create an entire genome. Though living cells routinely make long stretches of DNA, a DNA synthesis machine can't do the same.
In May 2010, researchers at the J. Craig Venter Institute announced their solution to this problem:
- Step 1. Using yeast cells to stitch together thousands of fragments of DNA made by a machine;
- Step 2: pooling the longer pieces;
- Step 3: repeating the process until the genome was complete;
- Step 4: inserting the genome into bacterial cells that are about to divide and grow the bacteria in a medium hostile to all cells except the ones harboring the synthetic genome.
The researchers tried their solution. And it worked! We are now able to create bacteria which are the first living creatures with a completely artificial genome. The microbes' entire collection of genes was edited on a computer and assembled by machines that create genetic fragments from chemicals and by helper cells that pieced those fragments together.
The same researchers have also developed a faster, yeast-free way to assemble large pieces of DNA in a bottle. They are using these methods to rapidly synthesize the viral DNA needed to speed up the production of influenza vaccines.
The creation of the synthetic cell is part of an effort to design a "minimal cell" containing only the most basic genome required for life. Synthetic biologists could use this minimal cell as the basis for cells that efficiently produce biofuels, drugs, and other industrial products.
Right now, the technique for incorporating his synthetic genome into living cells works only with mycoplasmas, which are useful for experimentation but not for industrial purposes. By adapting this system to work with a broader group of bacteria, it could be used to speed up the process of engineering microbes that make a wide variety of products.
At least two challenges remain:
1. Developing appropriate recipient cells for genome transplants, and
2. Finding ways of working with even larger pieces of DNA.
(Source: Technology review, MIT)
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