The US National Institutes of Health (NIH) has reiterated its stance against modifying human embryos, after a paper published last week by Chinese researchers reported how they modified the DNA of human embryos to eradicate certain inheritable diseases from the lineage. Modifying human embryos was banned in 1996 for US government bodies, but in some states private entities are allowed to carry out such research.

embyro genetic modification

Image: Genetics and Society

Though the agency’s policy against embryo modification is well known, NIH director Francis Collins found this is a good time to spell it once again. In his statement, Collins outlines the enormous benefits humanity might gain from genomic research like understanding genetic diseases, create resistance to HIV and so on. Using gene-editing technologies in human embryos, however, is a line that shouldn’t be crossed, Collins says. The NIH director argues that there are both technical difficulties and ethical implications of altering genes in human embryos.

As a reminder, last week Junjiu Huang and colleagues at Sun Yat-sen University in Guangzhou reported in the journal Protein & Cell how they used the CRISPR-Cas9 gene-editing system to alter the DNA of a non-viable human embryo. The embryo is called non-viable because it was fertilized by two sperm. The goal was to remove a gene mutation that caused a potentially lethal blood disease called  beta thalassemia. Most of the embryos were either non affected or badly mutated.

The paper was previously refused for publication by Nature and Science for unspecified reasons. We can guess, however, that they chose not to because of ethical implications and negative PR. In light of the controversy that spewed from the research, Protein & Cell (owned by Springer) defended the Chinese researchers and explained why the journal decided to publish the paper.

“Because germline modification is permanent and heritable, it should be given the particular concerns…In this unusual situation, the editorial decision to publish this study should not be viewed as an endorsement of this practice nor an encouragement of similar attempts, but rather the sounding of an alarm to draw immediate attention to the urgent need to rein in applications of gene-editing technologies, especially in the human germ cells or embryos.”

Other researchers in America, however, don’t agree with Collins.

“I am not in favor of the NIH policy and I believe that the Chinese paper shows a responsible way to move forward,” says David Baltimore, a biologist at the California Institute of Technology in Pasadena. “But it is the will of Congress that there be no work with human embryos and I assume that means even ones that are structurally defective.”