Gene editing, a scientific advancement allowing precise modifications to DNA, garnered global attention in late 2018. This field, promising for treating genetic diseases, gained international attention due to a controversial announcement from a Chinese scientist. The revelation sparked widespread discussion regarding the boundaries of scientific research and the ethical considerations surrounding human genetic manipulation.
The Landmark Experiment
In November 2018, Chinese scientist He Jiankui announced he had created the world’s first gene-edited babies, twin girls known by the pseudonyms Lulu and Nana. He Jiankui, an associate professor at Southern University of Science and Technology (SUSTech) in Shenzhen, China, used CRISPR/Cas9 technology to modify the embryos. His goal was to confer resistance to HIV by targeting the CCR5 gene.
The experiment involved couples where the father was HIV-positive and the mother was HIV-negative. He performed in vitro fertilization, then edited the embryos’ genomes to disable the CCR5 gene. A third gene-edited baby, named Amy, was born in 2019.
The Ethical Firestorm
He Jiankui’s experiment was met with widespread ethical condemnation. A primary concern was the lack of informed consent from the participating couples and the secrecy surrounding the project. The procedure also lacked medical necessity, as established methods like sperm washing can prevent HIV transmission from father to child without altering the embryo’s genes.
The irreversible nature of germline editing, which makes changes that can be passed down to future generations, raised ethical questions about unintended consequences for future generations. The experiment violated international scientific and ethical guidelines, including those from the World Health Organization, which advise against human germline modification for reproduction. He Jiankui also forged ethical review documents, exacerbating the ethical breaches.
Scientific Implications and Risks
The gene editing performed by He Jiankui utilized CRISPR-Cas9, a technology described as molecular scissors that precisely cuts DNA. This tool carries scientific risks, particularly when applied to human embryos. One concern is “off-target edits,” where the CRISPR-Cas9 system makes unintended changes to genes other than the targeted CCR5 gene. These alterations could disrupt normal cellular activities, potentially leading to unforeseen health issues or new genetic mutations.
Another risk is “mosaicism,” a condition where not all cells in an organism carry the intended gene edit. This means some cells might have the modified CCR5 gene, while others retain the original, unedited version, leading to variable gene expression and potentially incomplete protection or unpredictable outcomes. The CCR5 gene’s function extends beyond HIV entry; it regulates various cell types and immune responses. Its alteration could impact other viral diseases, such as West Nile virus. The long-term health consequences for the gene-edited individuals remain unknown, as the CCR5 gene’s full functions and the effects of its modification are still being studied.
Global Reaction and Aftermath
The announcement of the gene-edited babies provoked widespread international outrage from scientific organizations, governments, and bioethics committees. More than 100 scientists signed a petition calling for greater oversight of gene editing experiments. His university launched an investigation and dismissed him in January 2019.
Chinese authorities suspended his research activities shortly after the revelation. In December 2019, a Chinese court found He Jiankui guilty of illegal medical practice and sentenced him to three years in prison, along with a fine of 3 million yuan (approximately $430,000 USD). Two of his collaborators, Zhang Renli and Qin Jinzhou, also received lesser prison sentences and fines. This event led to calls for moratoriums on germline editing from scientists and international bodies.
Lingering Questions and Future Directions
He Jiankui’s experiment has had a lasting impact on the field of gene editing and global bioethics discussions. The long-term health and development of Lulu and Nana, and the third child Amy, remain subjects of ongoing concern and scientific inquiry. The incident prompted the World Health Organization to issue guidelines on human genome editing. Various governments, including China, have since prepared new regulations to prevent similar occurrences. This event shaped public perception and intensified the debate surrounding the responsible application of human germline editing.