(AP) -- For the first time in the United States, scientists have edited the genes of human embryos, a controversial step toward someday helping babies avoid inherited diseases.
The experiment was just an exercise in science — the embryos were not allowed to develop for more than a few days and were never intended to be implanted into a womb, according to MIT Technology Review, which first reported the news.
Officials at Oregon Health & Science University confirmed Thursday that the work took place there and said results would be published in a journal soon. It is thought to be the first such work in the U.S.; previous experiments like this have been reported from China. How many embryos were created and edited in the experiments has not been revealed.
The Oregon scientists reportedly used a technique called clustered regularly interspaced short palindromic repeats (CRISPR), which allows specific sections of DNA to be altered or replaced. It's like using a molecular scissors to cut and paste DNA, and is much more precise than some types of gene therapy that cannot ensure that desired changes will take place exactly where and as intended. With gene editing, these so-called "germline" changes are permanent and would be passed down to any offspring.
The approach holds great potential to avoid many genetic diseases, but has raised fears of "designer babies" if done for less lofty reasons, such as producing desirable traits.
Last year, Britain said some of its scientists could edit embryo genes to better understand human development.
And earlier this year in the U.S., the National Academy of Sciences and National Academy of Medicine said in a report that altering the genes of embryos might be acceptable if done under strict criteria and aimed at preventing serious disease.
"This is the kind of research that the report discussed," University of Wisconsin-Madison bioethicist R. Alta Charo said of the Oregon report. She co-led the National Academies panel but was not commenting on its behalf Thursday.
"This was purely laboratory-based work that is incredibly valuable for helping us understand how one might make these germline changes in a way that is precise and safe. But it's only a first step," she said.
"We still have regulatory barriers in the United States to ever trying this to achieve a pregnancy. The public has plenty of time" to weigh in on whether that should occur, said Charo.
One prominent genetics expert - Dr. Eric Topol, director of the Scripps Translational Science Institute in La Jolla, California - said gene editing of embryos is "an unstoppable, inevitable science, and this is more proof it can be done."
Experiments are in the works now in the U.S. using gene-edited cells to try to treat people with various diseases, but "in order to really have a cure, you want to get this at the embryo stage," he said. "If it isn't done in this country, it will be done elsewhere."
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