It is not the usual way for top scientists to announce their findings to the world, but on Monday, Jiankui released a video proclaiming that he had produced the world's first human babies whose genomes were edited using the powerful technique called CRISPR. He had also previously spoken with the Associated Press about his study, which he said resulted in twin girls born with the first genomes edited by the man.
The report was received with immediate concern and skepticism by the scientific community. His experience altered the genomes of embryos produced by in vitro fertilization; its genetic changes will therefore be passed on to any future generations. In addition, most CRISPR experts are not convinced that the technology is ready – or safe – for the treatment of humans.
"Given the current state-of-the-art genome-editing technology, I am in favor of a moratorium on deploying edited embryos … until we first have a set of security requirements," said Feng Zhang, one of the co-discoverers CRISPR and the Broad Institute at MIT and Harvard, said in a statement responding to the report. "Not only do I see this as risky, but I am also deeply concerned about the lack of transparency surrounding this judgment."
By 2015, prominent members of the scientific community familiar with the technology, including Zhang and another co-discoverer, Jennifer Doudna of the University of California, Berkeley, agreed to voluntarily stop research on the use of CRISPR in human embryos because the safety and the consequences in the long run the technology was very uncertain. Researchers support studies in which CRISPR is used to develop treatments that affect cells that are not passed on to the next generation – that is, anything but ovum and sperm – but say more research is needed before CRISPR is used to make changes in the genomes that can be transported by generation after generation.
Although editing the DNA of a human embryo is not currently allowed in the US in 2017, an international committee of the National Academy of Sciences called for the loosening of the moratorium and allowed CRISPR trials on human embryos under strict supervision to treat rare cases. genetic diseases that can not be addressed in any other way. In the UK, authorities have approved CRISPR studies on human embryos in 2016, but these embryos will not be transplanted to create a pregnancy. These tests call for embryo destruction after a week, as the safety of the technology is still unclear.
He, on the other hand, apparently jumped forward to produce the first human babies born with the CRISPR edition. He is a faculty member of the South University of Science and Technology in Shenzhen, China, but in a statement released in response to He's videos, the university said he is on unpaid leave from February 2018 to January 2021 ; employees did not provide a reason for the license.
"The University was deeply shocked by this event and took immediate steps to reach Dr. Jiankui He for clarification," authorities said in the statement. "The survey was conducted off campus and was not reported to the University or the Department. [to which He belongs]. "The statement continued by noting that the university" believes that Dr. Jiankui's conduct in using CRISPR / Cas9 to edit human embryos has seriously violated academic ethics and codes of conduct … The University will ask international experts to form an independent committee to investigate this incident and disseminate the results to the public. "
CRISPR, first described in 2012, provides scientists with the most accurate and effective way to edit the human genome by eliminating offensive mutations or genes and allowing the genome to repair itself or provide researchers with the ability to insert new genetic materials to correct disease genes. . But studies suggest that CRISPR control in human cells remains a challenge; in some cases, CRISPR may cut unintentional parts of the genome.
In his promotional video, he describes how to target the CCR5 gene, which helps the HIV virus enter healthy human cells. He worked with seven heterosexual couples in which the male partner was HIV positive and the women were HIV negative. After the couples produced embryos by in vitro fertilization, he used CRISPR to cut the CCR5 gene, disabling it in the hope of making the embryos less vulnerable to HIV infection. He states that out of 22 embryos, 16 showed signs of success in the CRISPR edition, and 11 were implanted, resulting in a single pregnancy with twin girls who were born in November. One of the twins, according to the He tests, showed signs that both copies of the inherited CCR5 gene (one from his mother and one from his father) were successfully altered, while the other twin showed that a version of the gene that inherited was changed.
That so-called mosaicism, in which some but not all of the embryo's cells are altered, is worrisome because in this case, this would mean that the girl can not be fully protected against HIV infection, like her sister. That's one reason researchers are worried about the report. Usually, these scientific landmarks are reported in full scientific journals with detailed descriptions of how the researcher performed the feat along with the data supporting his claims. Without this documentation, it is impossible to verify whether the girls actually exhibited a successful CRISPR edition or not.
He, who has created two companies based on his studies, is expected to present his findings at the Second International Summit on Human Genome Editing, and will certainly be the subject of numerous questions from leading gene editing scientists.