美国国家公共电台 NPR Scientists Closer To Creating A Fully Synthetic Yeast Genome（在线收听）

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Scientists have taken a big step towards making synthetic life. In other words, they figured out how to create a living thing with DNA that was written in a lab. NPR health correspondent Rob Stein has the details.

ROB STEIN, BYLINE: The scientists started with a critter that's pretty simple, yeast - you know, the stuff we use every day to bake bread, brew beer and ferment wine.

JEF BOEKE: We are essentially swapping out the code, if you will, in a living yeast cell with sort of a 21st-century version of the operating system.

STEIN: That's Jef Boeke of New York University. He's leading an international project to create yeast that are programmed with DNA that scientists manufacture in their labs. So far, they've created about one-third of yeast's chromosomes and shown they can work in living yeast cells even when they've rewritten big chunks of the code.

BOEKE: We can kind of torture the genome of the yeast in some pretty extreme ways, and the yeast sort of shrugs its shoulders and doesn't seem to care that much about it.

STEIN: So why are they doing all this? Well, one goal is to learn new things about basic biology.

BOEKE: Yeast kind of serves as a model for how human cells and other cells - how they tick. They are a great model for understanding the basic wiring of higher cells.

STEIN: The scientists also hope to create new forms of synthetic yeast powered by synthetic DNA to use like little factories to manufacture a lot more than just beer, wine and bread.

BOEKE: We're also developing some really practical tools for improving the yeast so that it can do a much better job at making useful products for us.

STEIN: Like new drugs to cure diseases. The scientists also want to create synthetic forms of other much more complex organisms.

BOEKE: This is absolutely setting the stage for being able to do these kinds of manipulations on a much larger scale in much larger genomes, such as those of plants and animals and even of the human genome.

STEIN: In fact, he's already working on another project that's trying to write a synthetic human genome with George Church, a Harvard geneticist.

GEORGE CHURCH: This is a whole new era where we're moving beyond little edits on single genes to being able to write whatever we want throughout the genome. The goal is to be able to change it as radically as our understanding permits.

STEIN: Now, some worry synthetic microorganisms, plants and animals could mess up the environment if they were ever released on purpose or accidentally and that terrorists could use this kind of technology to brew up new biological weapons. And Boeke knows that the prospect of creating a synthetic human genome sets off all kinds of alarm bells.

BOEKE: The biggest concern of course is people are worried that our goal is to make a synthetic human, a human powered by a synthetic genome. And this is why we are very adamant that our applications are in engineering of cells that could be used for therapies for humans. Don't make an organism from it.

STEIN: But some think society needs a lot more debate before anyone tries to manufacture a synthetic human genome in their lab. Laurie Zoloth is a bioethicist at Northwestern.

LAURIE ZOLOTH: Having that kind of knowledge and that kind of power over the human genome in a world as riven by injustice as the world in which we currently live would not be a good way to go, would not be a justifiable direction.

STEIN: Now Boeke says his group is moving very carefully with a lot of ethical oversight, and they hope to finish creating their fully synthetic yeast genome by the end of the year. Rob Stein, NPR News.

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