美国国家公共电台 NPR Editing Embryo DNA Yields Clues About Early Human Development（在线收听）

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For the first time, scientists have altered the DNA in human embryos to make a fundamental discovery about early human development. Scientists say this proves that modifying genes and human embryos can reveal powerful insights into the earliest days of human life. NPR health correspondent Rob Stein explains.

ROB STEIN, BYLINE: Tinkering with genes in human embryos has long been considered off-limits because of fears it could mess up the human gene pool or lead to genetically modified human beings. But scientists like Kathy Niakan of the Francis Crick Institute in London have argued that they could make big discoveries about basic human biology.

KATHY NIAKAN: The purpose of this research is to uncover insights into the function and the role of key genes in this important, critical window of human development.

STEIN: When a single cell somehow begins the journey towards becoming a fully formed human being. So Niakan's team used a powerful new gene editing technique to inactivate a single gene in dozens of very early embryos.

NIAKAN: This research is really the first time that genome editing has been used to study the function of a gene or the role of a gene in human embryos.

STEIN: And the results of the experiment were dramatic. Most of the embryos that had their gene inactivated failed to develop normally. The gene's called OCT4.

NIAKAN: So that tells us that OCT4 is really important.

STEIN: Important because a lot of women can't get pregnant or have miscarriages because they can't make healthy embryos. So this provides clues to how doctors could someday help them.

NIAKAN: This is opening up the possibility of using genetics - a genetics tool - a really powerful, precise genetics tool to understand gene function and to unlock a lot of important aspects of our human biology.

STEIN: The researchers also discovered the gene plays an important role in helping form the placenta, the organ that nourishes pregnancies. And that's not all. The OCT4 gene looks like it's a key player in embryonic stem cells.

NIAKAN: Embryonic stem cells have tremendous potential because they can help us to understand and even potentially treat diseases in the future as varied as heart disease, Alzheimer's and diabetes.

STEIN: Because of all this, other scientists say this is a big deal.

DEITRICH EGLI: It's a landmark study.

STEIN: Dietrich Egli is a biologist at Columbia University.

EGLI: The human embryo as an experimental system is a new groundbreaking concept that so far very few have dared to walk into. And this is something that Kathy Niakan clearly has done here in a pioneering way.

STEIN: But the research is also setting off alarm bells for some. While basic research like this could be important, Marcy Darnovsky of the Center for Genetics and Society worries about other scientists trying to take this too far.

MARCY DARNOVSKY: The concerns are that we would be opening the door to fertility clinics vying to offer gene editing to make future children taller or stronger or whatever they wanted to market. That could put us into a situation where some children were perceived to be biologically superior to other children.

STEIN: For her part, Niakan just hopes to learn more secrets about the basic biology of human development. Rob Stein, NPR News.