Published on April 18 in the journal Protein & Cell a study conducted by Chinese researchers who have edited the genomes of human embryos has raised a lot of controversy around the world.
Junjiu Huang is the lead author of the study. He is a gene-function researcher at Sun Yat-sen University in Guangzhou. The team of researchers involved in the study used the CRISPR/Cas9 technique to cut and replace the DNA in non-viable embryos. The embryos were created from eggs fertilized by two sperms therefore they could not result in a live birth.
CRISPR/Cas9 is a gene-editing technique. The technique was used to edit the gene responsible for a fatal blood disorder known as Thalassemia. The disease involves the presence of less than normal amounts of protein which carry oxygen. Work in human embryos is a controversial issue because any genetic changes which are made will be passed to the future generations. This is known as germline modification.
The executive director of the Centre for Genetics and Society in Berkeley (California), Marcy Darnovsky, commented on this:
“No researcher has the moral warrant to flout the globally widespread policy agreement against altering the human germline.”
86 embryos were used for the experiment, out of which 71 survived and 54 were genetically tested. Only a fraction of the 28 embryos which were successfully spliced contained the replacement genetic material.
It cannot be clearly established whether the experiment can be considered germline modification since the embryos used were non-viable. Huang explained that he particularly chose embryos which could not have generated live birth. Bioethicist John Harris of the University of Manchester believes that this is not worse than in the case of IVF (in vitro fertilization) which involves discharging the non-viable embryos. According to him a moratorium (temporary suspension) of the research is not justified.
Other people believe that germline cells modification could be accepted as research. Stem-cell biologist George Daley of the Harvard Medical School (Boston) argued that using gene-editing techniques as CRISPR/Cas9 and other such tools on eggs, human embryos and sperm could help a lot with basic scientific questions which are not related to clinical applications. In addition, although the US National Institutes of Health (NIH) does not allow funding for this type of research, in many US states and in China it is legal to modify human embryos.
Professor Robin Lovell-Badge, head of the Division of Stem Cell Biology and Developmental Genetics at the Francis Crick Institute, declared that he does not agree with a moratorium because he believes it will not work well. He said that he is fully supportive of research carried on early human embryos in vitro, particularly when they are not needed for reproduction.
Image Source: AFTH