CRISPR – ‘cut and paste’ genetics?

CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats. No need to remember the long name, but I would make a note of crisper because we will hear about it a lot in near future. It already has been chosen the 2015 Scientific Breakthrough of the Year and I bet the headlines will bend over backwards to make it sound more terrifying and complicated, while the research advances.

I have already touched on GMO after the WHO approved a genetically modified salmon for consumption (you can have a quick look here). To summarize: when attempting a genetic modification, the idea is to alter the instructions of a organism so eventually it turns out somewhat ‘better’. Whether it is to improve, make stronger certain qualities, or fix an already existing problem. Let’s go back to the concept of: DNA as organism’s library, RNA as notes taken from the library and then notes (RNA) used to make your cake (protein).

As I have mentioned before genetic engineering  is an overly complicated process: you have to find the perfect book, the perfect chapter, paragraph, sentence. If you are swapping something, the number of letters has to match, otherwise it simply won’t work. The book still has to be as masterpiece as it used to be. The change has to be extremely smooth.

So what is crisper changing?

Actually a lot: suddenly* gene editing is significantly easier to perform and success rates are much higher. Pre-crisper only very specialized labs, with super qualified people, state of art equipment and big grants were able to work with genetical engineering. Now the new technology makes it more accessible to an average scientist in an average lab.

*(in terms of science ‘suddenly’ can sometimes mean decades, in this case we are talking about massive developments since the 1st publication fully describing crisper mechanism in 2012, though the system was discovered in 1980)

How does it work?

It is based on a defense system used by bacteria to fight a viral infection. A virus will inject a bacterium with a piece of DNA (their viral instructions) to be multiplied by the host to form more viruses and infect further. The bacterium has a defense mechanism consisting of pieces of RNA working together with a protein called CAS9. These pieces of RNA work as spies looking out for the dangerous viral DNA pieces. Once they recognize them, CAS9 protein works as scissors cutting the dangerous DNA and this way deactivating it.

Scientists realized this system can be used to find and cut any piece of DNA, as long as the RNA spies are designed properly and of course we know what sequence we are looking for. This is when the beautiful idea of cutting out ‘broken’ genes was born. If DNA is cut, a living  organism will immediately try to fix it. When cutting out a ‘broken’ gene we can either hope the system will put things right afterwards or we can supply it with short pieces with the correct sequence that can be used for fixing.

I believe this video created by MIT researchers beautifully explains in a visual way how it works:

Does it mean we can be ‘corrected’ tomorrow?

Well, sorry to be disappointing anyone but no. The technology is just emerging, and not too soon the ethical discussions are being held around the globe. There are obviously concerns that while trying to fix one thing, changes and errors could be introduced somewhere else. And these new errors would be sitting in our genome, which means they can be passed to future generations.

For now it opens up possibilities of working with new species and looking into how we could safely apply that technology to help people get better. It can sound scary but on the other hand it could be one of the most important discoveries, not only of 2015, but of this century. I don’t know about you, but I am going to watch out for crisper. It really can change the concept of future medicine.

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