An international team of scientists based in Oregon just produced some truly extraordinary news – far more important than whatever spills out next from President Trump’s Twitter account. I speak of the recent modification of the genomes of 42 viable human embryos – an event likely to influence human societies for centuries to come.
This news likely catches most of us off guard, but scientists have seen it coming for years. One question now takes center stage: will the long-term consequences of this discovery be good or bad? The best path to an answer is to learn the science behind it and withhold judgment for now, not simply to rely on a gut reaction.
Many feel a visceral dread that scientists have awakened a monster – Move over, Frankenstein; designer babies are the future! To others the news triggers a raw fascination that humanity will now make a great leap forward – Scientists can stamp out all remaining human diseases, and we will inherit the keys to immortality!
Which of these two responses has more legitimacy? I submit both sides need to take a deep breath, and then keep their eyes and ears wide open before passing judgment. It will be months and likely years before we can adequately evaluate either possibility.
Science thrives on precision, and in this case it is important to understand precisely what happened. All human embryos possess a gene called MYBPC3 that controls development of heart muscles. Like all genes, MYBPC3 consists of a precise sequence of G, C, T and A nucleotides. The sequence is 20,000 letters long – roughly five times the length of this editorial.
Some human embryos possess a mutated version of the gene. Mutant sequences differ by just a handful of letters – like a long essay with a few spelling errors. Whoever inherits the mutant sequence develops abnormally thick heart muscles – a condition that forms the leading cause of death among young athletes.
People with this condition have a 50 percent chance of passing on the mutant gene to their offspring. For decades health professionals have wondered how to fix the “spelling errors” so the sequence would precisely match the normal gene.
Enter CRISPR, a revolutionary technique that allows scientists to edit precisely the nucleotide sequence of any portion of the genome – kind of like copying and pasting within a word-processing document.
In every organism it has been tried, CRISPR has worked. Because the molecular structure of human genes is indistinguishable from genes of other organisms, scientists never doubted CRISPR would work on humans. The only meaningful barriers were the Institutional Review Boards and other ethics committees that stand as gatekeepers for all human-based research.
These committees warmed to the potential benefits of genetically altering human embryos and have devised ways to minimize potential fears. For example, the MYBPC3 gene study was not provided any government funding, and it used only embryos not destined for implantation in a uterus. Researchers also succeeded in modifying just the targeted MYBPC3 gene without any “collateral damage” to other genes. In addition to last week’s study, CRISPR research on human embryos is taking place in the U.K., Sweden, and China.
And so the era of genetic modification of humans begins.
If you are one of those reacting with revulsion, you should ask yourself not only, “What might result?” but also “What is likely to result?” The history of technology is replete with discoveries that initially sparked fear and terror, but ended up becoming routine components of human society. Early satellites elicited prophecies of chaotic government surveillance, but they also led to unforeseen boons, such as mobile phones, improved weather prediction and incredibly precise maps. Likewise the editing of human genomes might produce dramatic benefits beyond what we perceive today.
Or perhaps not. New technologies are often a mixed bag. Nuclear technology from the Manhattan Project ended World War II and introduced a carbon-free energy source, but Hiroshima and Nagasaki were unmistakable tragedies, and no one is excited about a nuclear North Korea.
Regardless of how you feel about the editing of human genomes, I advise everyone to use this opportunity to learn science. Amazing science education resources are available such as RadioLab, hhmi.org, and just about any science museum. Understanding the DNA that makes your body tick could prove far more important for your welfare than perusing the ups and downs of an ever-changing news cycle.
Dave Gammon (firstname.lastname@example.org) is an associate professor of biology at Elon University in Elon, N.C.