Chinese researchers crossed a threshold last year when they used CRISPR-Cas9 gene-editing tools to modify human embryos, and now Oregon researchers have reportedly crossed it as well.
A report in MIT Technology Review suggests that the team at Oregon Health and Science University in Portland improved upon the results from China by modifying embryos earlier in their development.
OHSU confirmed that a study was in the works, but said there was nothing more to share at this time.
“Results of the peer-reviewed study are expected to be published soon in a scientific journal,” OHSU spokesman Erik Robinson said in an email to GeekWire.
Genetic experiments with embryos are controversial because they could involve changing the human genetic code in ways that can be passed along to a person’s progeny. That raises the prospect of creating subspecies of genetically modified humans with enhanced traits.
In recent years, CRISPR-Cas9 and other gene-editing techniques have revolutionized biology because they make it much easier to splice in or remove targeted strings of genetic code. Extending the technology to the human genome could bring great benefits, said Charles Murry, director of the Institute for Stem Cell and Regenerative Medicine at the University of Washington School of Medicine.
“The implications are very large, because it gives us the ability to permanently eradicate a genetic disease from a family’s pedigree,” he said in a UW Medicine video. “As a physician, that’s something that’s extremely exciting to me.”
However, the procedure isn’t perfect: The Chinese researchers reported off-target effects and a high incidence of mosaicism – that is, a mishmash of cells, some with the altered genetic coding and some without.
The Tech Review report quoted unidentified sources as saying that the OHSU researchers, led by Shoukhrat Mitalipov, headed off those problems by injecting human eggs with the CRISPR molecular tools simultaneously with in-vitro fertilization.
The sperm for the experiments came from men who had a genetic defect. The aim of the experiments was to see whether CRISPR could correct the defect, which went unspecified in Tech Review’s report.
The embryos were reportedly allowed to develop for no more than a few days.
Most countries, including the United States, have banned the implantation of genetically modified human embryos to produce a pregnancy. In 2015, the National Institutes of Health said it wouldn’t fund gene-editing research on human embryos. It’s legal to conduct such research for purposes that don’t involve making babies, but the ethical questions are the subject of sharp debate.
This February, a scientific advisory group convened by the National Academy of Sciences and the National Academy of Medicine said that “heritable genome-editing research trials might be permitted, but only following much more research.”
Murry said the research raises deep philosophical concerns, as well as medical qualms.
“It’s a very profound thing when humans begin to rewrite our own genetic code,” he said. “And there are all kinds of chances to not only make corrections as we edit, but to make new mistakes as we edit. … We may inadvertently create problems in our attempt to solve others.”