BY: NATHANIEL ASTUDILLO
A genetic editing system named CRISPR/Cas-9 has been successfully used on mice, zebrafish, plants, monkeys, and rabbits, to name a few. The entire human genome has been completely sequenced as of April 2003, and genome research has faced opposition along every step of the way. CRISPR/Cas-9 is no exception, especially given that humans have been added to the list of species whose code we can edit.
The part we can code is the guide RNA. When it forms a complex with Cas-9—the part of the CRISPR system that cuts DNA—any gene can be targeted. In fact, it’s as easy as filling out a web form. There are currently 12 design platforms available, 11 of which can be used straight from your browser. You select the organism you’d like to edit, search for your gene (it has autocomplete), and click “Generate Designs.” There’s a short wait, then a completion message. The popup closes, and you’re staring at a list of target sequences and their related data. You select your target gene’s matching RNA guide, and it’s put into your digital shopping cart.
DNA is a little bit like biological binary, using four letters to store information instead of ones and zeroes. A long sequence of the nucleotides A, C, T, and G, which are, respectively, Adenine, Cytosine, Thymine, and Guanine, match up as base pairs (A with T and C with G) to form DNA’s double helix. That structure defines every physiological aspect of the human body, including those that affect our temperament. There may be, after all, an idiot gene. As more discoveries reveal the functions of our two-hundred and fifty thousand some genes, scientists are working to crack that code.
DNA is a little bit like biological binary, using four letters to store information instead of ones and zeroes, which defines every physiological aspect of the human body.
If nucleotides are binary, then genes are the language we’re coded in. Think C++. Each gene contains the instructions necessary to make proteins, which are the building blocks of life, or sticking to our computer analogy, the “programs” that make up our biological system. Proteins are responsible for our body’s structure, function, and regulation. Then, CRISPR-Cas9, with its RNA guide, is our terminal.
The hacking doesn’t take place in a computer but in a lab. The 100 and 26-step process takes roughly a month. In short, you inject the cell with the Cas-9/guide RNA complex and the DNA segment(s) you want to be inserted as homology arms. As of now, the technique can edit multiple genes at once. Cas-9 finds and snips the gene, and the chosen single DNA strand is worked into place by the cell itself. It completes the repair, adding complementary base pairs to the single strand.
The technology has already been used to genetically engineer mice. It’s more efficient than the other gene editing techniques currently in use—TALENS and ZFNs—with a reported efficiency of more than 70 percent, more than 20 percent higher than TALENS and ZFNs. There hasn’t been any super strength yet, but there has been a lot of shortening of the time it takes to engineer a mouse to exhibit the symptoms of the inserted genetic disease to be studied. Normally, it takes about a year of breeding and several generations of mice to get that same result. Now, it’s a matter of weeks. That means that we can study genetic disease at a faster rate than ever before. It’s a major leap forward.
CRISPR/Cas-9 has been successfully used on mice, zebrafish, plants, monkeys, and rabbits, to name a few.
In fact, you could say we’ve become gods. If life is up for tweaking, where should we place its sanctity? Before CRISPER/Cas-9, the ethical debate was on human cloning. In both cases, we’re playing with life. Some folks would argue that the authority to control life lies with the gods. Others would argue that the use of gene editing technology opens up the possibility of people having control over the aesthetic qualities of their children.
They aren’t wrong. CRISPR/Cas-9 could very well be the tool that allows for designer babies. But it’s far off. The CRISPR/Cas-9 method is far from perfect. The system introduces the possibility of insertion/deletion (or indel), mutations at the site of the cuttings. Our cells naturally mutate with each division, and in somatic cells, the mutations usually aren’t severe enough to cause any debilitating changes. Even if they are, our bodies are designed to kill off cells that go awry.
The real concern comes in when we start editing germline cells. Their genomes can be passed onto future generations. Problems may show up generations down the line. Most scientists are in agreement that before we move onto actually making designer babies, we need to figure out the risks of gene editing technology and how to minimise them.
Most scientists are in agreement that before we move onto actually making designer babies, we need to figure out the risks of gene editing technology and how to minimise them.
Risks aside, the benefits of gene editing technology are hard to overlook. Genetic diseases could be cured before the person is even born. Cystic fibrosis, Huntington’s disease, Down syndrome, muscular dystrophy, anaemia, celiac disease, autism, cancers, diabetes, and mood disorders are just a few. The quality of life for patients with genetic disorders would be a tremendous improvement. There are even methods being developed to deliver CRISPR/Cas-9 to developed organisms. In vivo experiments on mice have shown that, in an adult specimen, tyrosinemia—an inherited liver disorder that can be fatal if left untreated—can be cured.
For now, scientists in the UK are allowed to edit the human genome, provided that the cells are harvested before by the fourteenth day of their development. The current legislation also prevents edited human embryos from being implanted into a womb, so designer babies are a definite legal no go until that’s called off. Some countries, such as Italy and Germany, have a complete ban on research involving human embryos. As was the case with in vitro fertilisation, public opinion has grown more relaxed and accepting, and I see the same sort of scenario happening for CRISPR/Cas-9.
Genetic editing is one of those things that feels like its come straight out of science fiction. It opens up new realms of possibility, and they’re equal parts frightening and exciting. With a web form and a laboratory, we can change the parts of us that define us. Whether or not the results end up in a biohazard bin or a crib, it’s certainly something to explore. There’s an old hacker’s adage that reads, “Every program has a bug.” Human genes have a lot of them. I say we change some letters and fix them.