Last week, it was announced that the Chinese used CRISPR-edited cells in a living, breathing, human being.
Let me back-up a little bit.
CRISPR stands for clustered regularly interspaced short palindromic repeats, which are “segments of prokaryotic DNA (unicellular organism that lacks a membrane-bound nucleus) containing short repetitions of base sequences” with one DNA sequence in particular repeating over and over again, creating unique sequences in the repeats. They then discovered that these unique sequences mirrored the DNA of malevolent, bacteria attacking viruses.
Basically, the bacteria was keeping parts of the virus around so it would prepared the next time the virus attacked.
“The second part of the defense mechanism is a set of enzymes called Cas (CRISPR-associated proteins), which can precisely snip DNA and slice the hell out of invading viruses. Conveniently, the genes that encode for Cas are always sitting somewhere near the CRISPR sequences."
There are many different types of Cas enzymes, but the most well-known, called Cas9, comes from Streptococcus pyogenes, more commonly known as the bacteria that causes strep throat.
Finally. I’ve mentioned something recognizable.
Together, they are the CRISPR/Cas9 system. Cas9 cuts the DNA and CRISPR tells Cas9 where to cut.
About four years ago, this naturally occurring DNA sequencing system was turned into a gene editing machine called CRISPR. Since, it has been used to combat viruses, sterilize mosquitos (West Nile, anyone?), prepare pig organs for human transplant, and fix genetic diseases in animals. The machine has been quite revolutionary because it’s cheap and easy to use. If you have access to the tool, all you need is an RNA guide, something most scientists can order online. One the RNA guide is programmed in, CRISPR hones in on the matching RNA in the DNA sequence and gets to work. With a basic understanding of genetics, even a caveman could operate it.
In September, a Swedish scientist, Fredrick Lanner, announced that he was using CRISPR to edit healthy human embryos. The Chinese had previously reported, twice, that they had been editing human embryos as well, but embryos that were unable to develop into a baby. Lanner used embryos left over from an in vitro fertilization process.
Now, the Chinese have gone a step further. Last month, scientists at Sichuan University “injected cancer-fighting, CRISPR-modified white blood cells into a patient suffering from metastatic lung cancer.” The idea is that the modified cells will seek out the cancerous cells and wipe them out. The results of the process are still pending.
Does anyone else think this potentially could get out of hand?
We aren’t the only ones. Last December, scientists from the National Academy of Sciences, the Institute of Medicine, the Chinese Academy of Sciences, and the Royal Society of London, gathered in Washington to discuss the risks associated with editing the human genome. “Unlike gene therapy, an accepted medical technique that alters the body’s ordinary tissues, editorial changes made to the human germ-line would be inherited by the patient’s children and thus contribute permanent changes to the human gene pool. These, if sufficiently extensive, might, in principle, alter the nature of the human species."
So what was the consensus? While some scientists believed the human genome shouldn’t be edited at all, many argued the technology should be experimented with aggressively. What they all agreed on, is that the science should be fully explored and discussed before major advancements are made. While this group of international scientific communities isn’t an acting authority, the scientific community has been known to follow their guidance.
Sources: Wikipedia, Gizmodo, Wired, Science News