It’s December 1st and time to enjoy a little science and this decade’s revolution in genetics …. CRISPR. *Yeah sorry, nothing actually about Christmas except that it sounded like a cool title!
You might have heard quite a bit about CRISPR in the news on various topics: when the first ‘CRISPRbabies’ were born in China, uses in cancer treatments, and many other fields. There is much debate of the ethics and proper usages which I will address later. But first, what is CRISPR?
What it is
There are two things we need to address: first, CRISPR itself is the abbreviation for a group of DNA sequences called Clustered Regularly Interspaced Short Palindromic Repeats. As you may be able to interpret from the name, these are a set of regularly spaced DNA segments and are found in bacterial genomes. They form part of the bacterial immune system because the DNA between each CRISPR sequence matches viral DNA (it acts as a genetic memory). If invaded by a virus again, the appropriate DNA segments are transposed to RNA and “instructs” a nuclease (a cool-DNA cutting protein) to go “cut up” the corresponding section of DNA in the invading virus. Once the viral DNA is severed, it is often unable to then continue to replicate its DNA and dies, thus protecting the bacterium.
Secondly, those nucleases are given a special name, Cas (named inventively for CRIPSR associated). Together, CRISPR-Cas9 is a gene-editing technique that is related to CRISPR sequences and uses this idea to be able to edit and change genes at very precise or pre-programmed locations along a chromosome. Understanding what CRISPRs are is important to understanding how the associated gene-editing techniques work and how they are used today.
The History of CRISPR
This journey began fairly recently when scientists first noticed these CRISPR DNA sequences in bacterial genomes by a Spanish scientist, Francisco Mojica. This was as early as the 1990s, and he eventually named these DNA sequences by the name we know them today, CRISPR. He hypothesised that these sequences formed part of the bacterial immune system, however this was not experimentally demonstrated until 2007.
Later, in 2012 and 2013, was when the rest of the world started really hearing about CRISPR. Why?
Because it was exciting. Several research groups had demonstrated that the CRISPR-Cas9 mechanism had been used to actually edit genomes. Other, previous gene-editing processes were lengthy, expensive and difficult to carry out. CRISPR wasn’t. It was quick and easy and relatively cheap. And so a revolution began.
The Future: Technology and Ethics
Quickly after this point, CRISPR has been further developed and extended upon. It has been suggested for multiple genome-editing applications, such as genetically engineering better crops, correcting genetic mutations and many other areas of research in genetics, both genetic engineering and in simply extending our knowledge of genetics.
Seeing as CRISPR is a far cheaper way of genome editing (costing up to 150 times less than previous methods), it is far more accessible to research labs around the world. This means that more people can perform it, and that research and techniques can progress rapidly. We’ve already seen massive advances in the past few years even.
Clearly we have the above applications that are areas of great interest. But also, there’s strong interest in medical advances and technologies. Imagine, for example, being able to correct genetic diseases by cutting out and replacing the defective DNA sequence! It’s also an invaluable tool in medical research in cell or animal models, to rapidly and effectively recreate or fix genetic issues, allowing us to advance that knowledge.
However, as you can imagine, there are massive ethical implications. If we edit a human genome, any of their children would carry the same edit. If it was beneficial (such as curing a genetic disease), we would have few issues. But what if the process went wrong? Or had unintended consequences? Or is an “aesthetic” change to try and create a “better person”? Then any children or further generations would carry this without having had a choice. And if we genetically engineer some people to be superior, then this would probably cause greater social division between classes, races and ethnicities than before.
There are numerous ways to misuse and abuse this technology, which is why we must be so careful to adhere to ethical guidelines.
This is something we heard a lot about last year, with the announcement of Chinese scientist, He Jiankui, having edited the genomes of several babies as embryos. The idea was to remove a gene that codes for a protein that would allow the HIV virus into cells. Without this gene, the idea is that these children would not be susceptible to this disease. However, it is not known whether this has been successful or whether these children are going to have a lowered immunity to other disease or other side-effects. Not only this, these children will grow up being known as the “first CRISPR-children”. All of this without their consent or permission.
This became an international scandal, and has since resulted in a 3-year prison sentence for He and lesser sentences for his colleagues for flaunting ethical regulations. This is only one example of how easy it was for one person to potentially alter the entire lives or future generations of people, potentially in a good way, but also very potentially harmful, and without the appropriate ethical permissions.
While this is an incredibly exciting technology, and will continue to be developed and advanced in years to come, we also have many reasons to give ourselves pause, properly test methods and give ourselves a note of caution before becoming carried away.