Of all the prodigious advances in technology taking place today, none is more profound — and troubling — for the human condition than the advent of gene editing and synthetic biology.
Corrective intervention in the human genome promises the elimination of genetically induced disease, bolstering of the human immune system, and extended longevity. As Nobel laureate and former president of Caltech David Baltimore said to The WorldPost in the video above, we already understand enough to create humans in which a range of ailments are edited out — and scientists have only been at it for less than a century.
Yet if that process trespasses ethical boundaries agreed upon today by responsible scientists, it could change the human genome forever by altering the “germline” — gene sequences inherited and passed down through generations. That could be for the better, but quite possibly for the worse, since the interrelated genetic functions developed over the long history of evolution remain unknown, despite the advances Baltimore notes.
While the ethical and regulatory focus of concern has been on “designer babies” or threats to the human germline, the high risk of unintended consequences also applies to editing the genes of other life forms, from mice and mosquitos to microbes.
Some of the top scientists, ethicists and legal experts in the field examine these issues in The WorldPost this week.
“Recent leaps in the biosciences, combined with big data analysis, have led us to the cusp of a revolution in medicine,” writes Craig Venter, who led the team that first mapped the human genome and remains on the frontier of new breakthroughs. “Not only have we learned to read and write the genetic code; now we can put it in digital form and translate it back into synthesized life. In theory, that gives our species control over biological design. We can write DNA software, boot it up to a computer converter and create unlimited variations of the gene sequences of biological life.”
Venter’s labs have so far succeeded in synthesizing a chromosome based on the chemical analysis of a segment of DNA and have designed an entirely new cell digitally, proving that all functions derive from that DNA implanted in the cell nucleus. This suggests that “sequencing” an individual genome — ordering the base pairs of a segment of DNA — can be designed to edit out the defective genes that cause a particular disease.
Venter understands well the temptation of a permanent fix by changing the germline itself. But he warns that this red line should not be crossed because it can only be tested through experiments on humans. “The world agreed at the end of World War II to stop all direct human experimentation. Human germline editing would cross that boundary and take us back into random human genome editing, just to see what happens. We should not let this happen.” The cautious and responsible way to reach that aspiration, he argues, “is to continue enhancing our knowledge of the genome itself so that genome editing can become a legitimate part of the future of medicine.”
Jeantine E. Lunshof, an ethicist in the Church lab at Harvard Medical School’s Department of Genetics, worries that science is outpacing ethical considerations. As synthetic biology and technologies like the CRISPR editing tool enable ever bolder efforts — such as in China in 2015, when researchers genetically modified a human embryo — the most pressing issue has become how to draw the line, especially as lines are washed away by each new wave of discovery.
“One practical solution is to bring the philosophy and ethics toolbox to the floor of the lab itself, to the point where the lines begin to be drawn in the first place,” says Lunshof. “Ethicists are called upon when developments in the sciences elicit strong moral intuitions,” she concludes, “but an expert opinion needs hands-on, real-world data gathered in the biological engineering lab through direct interactions.”
If ethics is behind the curve of science in human engineering, Stanford professor Henry T. Greely also sees regulation as lacking when it comes to gene editing of non-human life forms.
“I support genome editing but it needs regulation, both to minimize possible risks and to reassure the public about its safety,” he writes. “And any regulation must be nuanced, to distinguish between different levels of risks in different uses. Editing Dalmatians in a kennel is more controllable than releasing millions of edited mosquitoes; modifying laboratory pigs to take out certain embedded viruses is safer than editing mousepox. Our current ‘system’ does not come close to those goals.”
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