A new generation of genetic engineering tools is giving rise to a practice that makes extreme body art look like child’s play. One of the most exciting is called Clustered Regularly Interspaced Short Palindromic Repeats, mercifully shortened to the acronym CRISPR. This new tool may be capable of doing a lot of good, but there’s always the risk of unintended side effects. Enter the body hackers:
On Oct. 4 at a biotechnology conference in San Francisco, Zayner says he injected himself with CRISPR, the powerful gene editing technology, to biohack the muscle cells in his forearm. "Well, it's not necessarily that I want bigger muscles," he says. "The thing is, that this is the first time in history that we are no longer slaves to our genetics. We no longer have to live with the genetics we had when we were born. Technologies like CRISPR and other genetic modification technologies allow adult humans to modify the cells in their body.”
Whether this will actually work or not remains to be seen. (Be skeptical.) But the principle is intriguing: many tissues in our bodies are constantly being broken down and rebuilt, what biologists call catabolism and anabolism, respectively. A substance called myostatin is heavily utilized during catabolism, and plays a key role in the break down of muscle tissue. So, if the gene[s] for making myostatin was removed, your body would “forget” how to produce it. This would in turn inhibit muscle break down. Muscles would still be able to grow larger and stronger, but would be resistant to breaking down and getting smaller and weaker.
Genetically modified lab animals have been created by processes like this, giving rise to the term knock-out mice. Something similar can happen from time to time in nature via mutation. One result is a hyper-muscled breed of cattle called Belgian Blues, like the mean looking beef-cake at the top of this post.
So how does one go about precisely snipping out a gene or two on the molecular level? That is an interesting story.
It seems at some point in the deep past, simple, humble bacteria had hung on to short genetic sequences from viruses looking to infect them and learned how to turn the tables on the little parasites using their own genetic code. Over time, and no doubt over countless generations of harsh natural selection, those bacteria refined the stolen sequences and incorporated them into an ever-more sophisticated immune system. It has since developed into an elegant response, where sequences of invaders are snipped out, and incorporated into an immune response that has a sort of acquired memory. Once a particular infectious pathogen has been sampled, the immune system leans and forever remembers how to fashion genetically targeted antibodies and other responses to that infection that stops the invaders dead in their little slimy tracks. Acquired immunity is not limited to bacteria! A similar acquired immune response in human cells is instrumental in the efficacy of vaccines.
The part of that system that snips out enemy sequences and transplants them in to the memory section of the immune control region in bacteria was found by molecular biologists, eventually isolated, finally replicated, greatly refined, and now makes up the new tool we call CRISPR. It acts like a tiny pair of scissors that allows geneticists to snip those gene sequences out of the DNA and leave the genome healthy and intact. It’s actually a lot more involved than scissors, but that’s the basic concept. What’s important to understand as far as the development goes, is we didn’t build CRISPR so much as domesticate it. The wild, untamed version was found unexpectedly inside bacteria years ago. So ring the gong for serendipitous scientific research!
Bear in mind, if you knock out a gene that has already been expressed, like the gene for blue eyes in an adult, the eyes won’t suddenly change color. Those genes have already been read and used to make the blue eyes in question. To change eye color in a grown person would take more than knocking out the genes for blue eyes. But there are other genes that are used over and over, every day—in some cases virtually continuously—like the gene that tells your cellular machinery how to make myostatin.
What could possibly go wrong? Obviously people should be skeptical of miracle treatments until they’re shown to be effective and safe. This has all the signs of modern day snake oil. It’s a good guess the market might soon be full of magical CRISPR-like elixirs claiming to do all kinds of things. CRISPR could become similar to the quack claims of stem cells: just inject them into the body and all kinds of cool things happen.
Our molecular biology is a lot more complicated than that. Here’s a fantastic video called the Inner Life of the Cell that illustrates just one tiny processes occurring deep inside a white blood cell to allow it to slip in between other cells, after it sniffs the telltale traces of inflammation and possible infection:
Most people would twice before throwing a wrench into that kind of complicated, living machinery!
On the other hand, the real deal might actually have an effect—and that’s even more dangerous. The long, complex chemical pathways by which molecules are created, used, and reused are beyond current computational power. Just the number of ways a single protein can be folded and interact with other tiny components can reach hundreds of orders of magnitude: that’s a one followed by hundreds of zeros! For all we know, myostatin could be reused in some other critical processes, and it could be a precursor to other substances that do important things. Slowing down the production of myostatin or any other gene-based manufacturing process could cause terrible, perhaps even fatal conditions to develop.
Then again, there is hope here. The potential treatments that tools like CRISPR might provide are borderline miraculous by today’s standards. Even on the purely cosmetic side, we all have something about ourselves we’d like to change, and probably more than one thing, if we are honest. So maybe the body hackers are doing us all a service by risking their health and their very lives. Only time will tell.