Ever since the 50’s, scientists have been using DNA to modify bacteria, plants and even animals. From tomatoes with a longer shelf life to glow-in-the-dark zebrafish. Recently, this technology witnessed a breakthrough, allowing scientists to be on the brink of curing HIV, among others. But this is just the beginning.
Genome editing is expensive, complicated and time-consuming. In the last few years, however, a process called CRISPR-CAS9 shrunk the costs of genome editing by 99% and shortened the time to conduct experiments to a couple of weeks instead of a year.
Picture: Three CAS9 proteins carrying a guide RNA (red), unwinding a DNA string (blue) and finding a virus DNA (yellow) in the string. This is going on in your body right now.
So how does it work? Every time a bacterium is attacked by a virus and survives the attack, it saves a part of the foreign virus DNA in its own genetic code archive called CRISPR, short for Clustered Regularly Interspaced Short Palindromic Repeats. When the virus attacks again, the bacterium uses the archived DNA (guide RNA) and links it to a protein called CAS9 (CRISPR Associated Protein 9). The guide RNA then literally takes the CAS9 armed with the archive DNA for a stroll along the DNA chain. Still with us? Good, because now things get interesting.
CAS9 then unwinds this foreign DNA and looks for parts in the DNA chain that are identical to the foreign DNA. Imagine a dog sniffing your sock and using that smell to track you down. When a match is found, CAS9 cuts the virus DNA out of the chain, protecting the bacterium from the attack, and replaces it with a healthy one. This is a natural process, it is occurring in your body right now.
Scientists at Temple University in Philadelphia used this method to cut the HIV virus out of living cells.
So what such a process that has been active since the dawn of life so interesting for genome editing? In recent years, scientists discovered that the CRISPR system is programmable. This means that in a lab, scientists can link up any DNA with CAS9 and place it into a living cell. The cell no longer needs to be attacked in order to possess a foreign DNA.
In 2015, scientists at Temple University in Philadelphia used this method to cut the HIV virus out of living cells. A year later, CRISPR-CAS9 was used to remove more than half of the HIV contaminated cells from infected rats. In the future, a CRISPR-CAS9 therapy might cure HIV and other viruses like herpes. It could even modify your immune cells to hunt for cancer cells, changing a cancer treatment to nothing more than a couple of injections of your own cells which have been modified in a lab.
But CRISPR-CAS9 is accurate. Very accurate. Modified versions of CAS9 – which are already being made – can fix just one letter of a DNA string. Knowing that your genetic code consists of a ‘DNA alphabet’ and that genetic diseases are usually one faulty letter in your DNA, these could become a thing of the past.
Over time, CRISPR-CAS9 can and will be used for genetically modified humans, also called designer babies. The first modified humans will not be overly designed, they will be created to eliminate a deadly genetic disease which runs in the family.
But, as technology evolves, so will the ethics. Will your grandchildren be irresponsible parents if they don’t choose a designer baby that doesn’t have your colour blindness, for example? What about perfect eye sight or extraordinary intelligence? Modified humans could become the new standard. As research and technology evolve even further, we could solve the single biggest mortality risk factor.
A combination of genetic engineering and other therapy could slow down, stop, or even reverse ageing. Several animals, such as lobsters, age much slower. Who knows what the possibilities are when we ‘borrow’ a few of those genes.
Research into slowing down the ageing process has just begun and many scientists are skeptical about it. The challenges are monumental and, as any other organism in the universe, eternal life is probably unachievable. However, what’s conceivable is that people alive today might be the first to profit from effective anti-ageing therapy.
As ever so often with new technologies and applications, the tip of the iceberg is all we know. Unpredictable consequences can still occur due to the complex interplay between our genes. And what about the dangers of CRISPR-CAS9? This technology might be a bit scary, but as a species, we have a lot to gain. We might end diseases or extend life expectancy by centuries.
Discover more of the opportunities, possibilities and threats during our Visionary Seminar on Thursday December 14 at imec where professional scientists map out where we stand and where we are going with CRISPR-CAS9, whereas professionals from the pharmaceutical industry show how they plan to implement CRISPR-CAS9 in their applications.