Scientists at the J. Craig Venter Institute, a controversial research group dedicated to creating artificial life, moved one step closer to their goal by synthesizing a genome of a bacterium, a new study reports.
The researchers built the longest artificial genome ever made using four chemicals that make up DNA, adenine, cytosine, guanine and thymine, according to the study published today by the journal Science. Scientists compare the sequences of those bases to identify genome differences among living creatures, from bacteria to humans.
Scientists hope to use artificial genomes to create bacteria designed to take on specific jobs, such as producing methane. Previously, the same scientists inserted the genomes of one bacterium into the cells of another. If they can use that method to insert the artificial genome into a cell, they’ll have created the first new life form controlled by a man-made genome.
A genome is the operating system of the cell,” said Hamilton Smith, a researcher at the Rockville, Maryland institute and study author, in an audio interview published by the journal. “I like the analogy with the computer. You have an operating system which by itself doesn’t do anything, but when you install it on a computer, then you have a working computer system. It’s the same with the genome. The two together make a living, reproducing cell.”
The latest research uses a new technique that may help scientist construct even bigger DNA molecules from chemically created pieces, according to the report. The scientists designed fragments of DNA to build 101 segments of 5,000 to 7,000 base pairs, the molecules that form the rungs of the DNA ladder. They connected the segments into four strands, which they inserted into yeast for the final connections.
The final chromosome was then checked against the sequence of the natural DNA to confirm that it was an accurate replica. The bacterial genome uses 582,970 base pairs. The longest previous stretch of artificial DNA was 32,000 base pairs, according to the institute.
Dr. Venter, 61, founded the lab to research ways to use artificial genes to build new organisms that could turn sunlight into fuel, clean up industrial waste, or monitor patients for the first signs of disease. The institute has made virus genomes, which are much smaller, in previous studies.
“It’s a wonderful breakthrough that could change the way we think about gene therapy,” said David Magnus, co-director of Stanford university’s Center for Biomedical Ethics. “It would it allow us potentially to create chromosomes exactly the same as a patient’s chromosome but with genes that have been corrected. This could be a future treatment for disease.”
Creating so-called designer organisms like this, and the potential to profit from them, are sparking both excitement and debate among scientists and venture capital investors.
“Venter is claiming bragging rights to the world’s longest length of synthetic DNA, but size isn’t everything,” said Jim Thomas, a program manager at ETC Group, an environmental advocacy group in Ottawa, in an e-mail. “The important question isn’t ‘how long?’ but ‘how wise?’ Regulatory oversight is stalled and there has been no meaningful or inclusive discussion on how to govern synthetic biology in a safe and just way.”
…this post forwarded by Windsor Humanist, Alexander Neil, after a January 24, 2008 article by Tom Randall and Bob Drummond in Bloomberg News