Researchers Create Largest DNA Structure -- But is it Life?
A team of 17 researchers at the J. Craig Venter Institute said it has created the largest man-made DNA structure by synthesizing and assembling the base-pair genome of a bacterium.
This work, published Thursday in the journal Science, is the second of three key steps toward the team's goal of creating a fully synthetic organism. The team's next task is to attempt to create a living bacterial cell based entirely on the synthetically made genome. But some scientists are arguing about the possibility of creating life in the lab.
"This is not an example of creating life. It's a new form of genetic engineering. There's a lot of hype about this, and that's not surprising. But we need to be really careful how we word this and how we look at this," said Dr. Georgia Purdom, a biologist and molecular genetics expert at the Creation Museum. "Even Craig Venter himself has said he is not creating life; he is modifying life to come up with new life forms using premade components."
'A Technological Marvel'
The Ventner team accomplished its feat by chemically making DNA fragments in the lab and developing new methods for the assembly and reproduction of the DNA segments. After several years of work on chemical assembly, the team discovered it could use homologous recombination (a process that cells use to repair damage to their chromosomes) in the yeast Saccharomyces cerevisiae to rapidly build the entire bacterial chromosome from large subassemblies.
"This extraordinary accomplishment is a technological marvel that was only made possible because of the unique and accomplished JCVI team," said J. Craig Venter, Ph.D., president and founder of the institute. "Ham Smith, Clyde Hutchison, Dan Gibson, Gwyn Benders and the others on this team dedicated the last several years to designing and perfecting new methods and techniques that we believe will become widely used to advance the field of synthetic genomics."
Building Blocks of DNA
The building blocks of DNA -- adenine (A), guanine (G), cytosine (C), and thiamine (T) are not easy chemicals to synthesize into chromosomes. As the strands of DNA get longer they get increasingly brittle, making them more difficult to work with.
Before the institute's announcement, the largest synthesized DNA contained 32,000 base pairs. So the institute's work building a synthetic version of the genome of the bacteria M. genitalium that has more than 580,000 base pairs presented a formidable challenge.
"When we started this work several years ago, we knew it was going to be difficult because we were treading into unknown territory," said Hamilton Smith, M.D., senior author of the report. "Through dedicated teamwork we have shown that building large genomes is now feasible and scalable so that important applications such as biofuels can be developed."
While Purdom may not agree that Venter's team could ever create life in the lab, she does not deny the importance of the study. She called genetic engineering of bacteria exciting.
"Venter's idea is having bacteria clean up toxic waste sites and clean our air. It definitely could be very beneficial to do this. Of course, everything like this has a downside," she said. "There's always the fear that you are going to create a bacteria that can infect people and be used as a bioweapon. That's always going to be a fear with any kind of new bacterial DNA technology."