Researchers from Oregon Health and Science University (OHSU) in Portland carried out the study, according to MIT's Technology Review.
Shoukhrat Mitalipov, head of OHSU's Center for Embryonic Cell and Gene Therapy and lead author on the research, explains that their study made use of the innovative technology CRISPR. The team didn't allow the embryos to develop for more than a couple of days, and they were never meant to be implanted into a womb. They then modified the mutation using a gene-editing technique, CRISPR. It's like using a molecular scissors to cut and paste DNA, and is much more precise than some types of gene therapy that can not ensure that desired changes will take place exactly where and as intended.
Scientists in China have published similar studies with mixed results.
Scientists like Mitalipov believe they can eradicate or correct genes that cause inherited disease and even cancer by altering the DNA of human embryos.
But earlier this year, NAS and the National Academy of Medicine said scientific advances make gene editing in human reproductive cells "a realistic possibility that deserves serious consideration".
"This is the kind of research that the report discussed", University of Wisconsin-Madison bioethicist R. Alta Charo said of the news of Oregon's work.
Some critics say germline experiments could open the floodgates to a courageous new world of "designer babies" engineered with genetic enhancements-a prospect bitterly opposed by a range of religious organizations, civil society groups, and biotech companies.
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CRISPR-Cas9 is a tool for making precise edits in DNA, discovered in bacteria. Critics worry, however, that gene-editing in embryos opens the floodgates to the creation of "designer babies" in which parents specify traits they want their children to have.
Human embryos have been edited with CRISPR before, only in China.
"If America were to take the lead both in terms of working with journals, working with private foundations, with patient groups, and working with state and federal government, I think you'd get collaboration from the rest of the world", Caplan says.
When cellular machinery repairs the DNA break, it removes a small snip of DNA.
Somewhat prophetically, Perry's paper on the research, published at the end of 2014, said, "This or analogous approaches may one day enable human genome targeting or editing during very early development".
Don't expect a new generation of gene-edited people in the U.S., though: Any local efforts to turn edited IVF embryos into babies have, so far, been blocked by Congress.