With the help of Johns Hopkins biomedical engineering students who spent years stringing bits of DNA together, scientists have built the world's first synthetic yeast chromosome, which eventually could help in the production of drugs, vaccines, biofuels and even beer.
Jef Boeke, a former Hopkins professor, started working on the research with students in 2007. Since then, about 60 took part in the "Build a Genome" class. A global team of researchers led by Boeke manipulated chunks of the DNA in a way that could engineer the chromosome to create desirable characteristics.
"We think that's going to be a very powerful tool for biotechnology as well as a way for us to learn something new about the biology of yeast," Boeke, director of the Institute for Systems Genetics at New York University since January, said in an interview Thursday.
Published Thursday in an online edition of the journal Science, the research is important in the field of synthetic biology, an emerging area of science that applies the principles of engineering to living systems. While other teams have synthesized bacterium and viral DNA, Boeke's is the first report of a synthetic chromosome in a eukaryote, an organism whose cells contain a nucleus, like the cells of most plants and animals, including humans.
Jim Collins of Boston University and a pioneer in the field called Boeke's work a "tour de force in synthetic biology."
"This development enables new experiments on genome evolution and highlights our ever-expanding ability to modify and engineer DNA," said Collins, whose lab won a Gates Foundation grant in 2012 to engineer a probiotic yogurt bacterium to neutralize cholera infections.
The scientists used computer-aided design to build the synthetic chromosome, a version of the naturally occurring chromosome III in brewer's yeast, known scientifically as Saccharomyces cerevisiae. While the chromosome in its natural state contains about 316,000 base pairs of DNA — combinations of the four types of macromolecules that are stacked to form DNA's signature double-helix structure — the scientists trimmed down the synthetic version to contain about 275,000 base pairs.
That sort of tinkering could, in theory, kill a yeast cell, but in this case, Boeke said, the changes showed that the chromosome is "hardy" and generates new properties in the yeast.
Synthetic strains of yeast could eventually be created that would be useful in production of medicines, like artemisinin, a malaria drug, or vaccines, including for hepatitis B, that are derived from yeast. Synthetic yeast could also make for more efficient production of biofuels or beer.
Lei Wang, assistant professor in the Chemical Biology and Proteomics Laboratory at the Salk Institute for Biological Studies in La Jolla, Calif., said the work "will enable us to artificially speed up the evolution process in the lab."
Wang, who was not involved in the research, said he was impressed to see the yeast behaving normally after so many changes, which suggests that "you can do very bold things to the organism."
Work to make synthetic versions of the yeast's 15 other chromosomes by 2017 is ongoing in labs in Britain, China, India and the United States — including in Hopkins' genome-building class.
Reuters contributed to this article.
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