Are we about to enter the era of designer babies, or just vegetables that take slightly longer to go limp? IA critical thinker John Turnbull looks at the latest developments in CRISPR/Cas9 technology and ponders a Gattaca-like future.
A short history of Genetic Engineering
Genetic engineering is a sensitive subject among many, invoking visions of fish-matos or monkeys with altogether too many asses. While these fears aren’t really based in reality, they’re often driven by a lack of knowledge about genetic engineering and the techniques involved.
While humans have been influencing the genome of plants and animals for centuries through selective breeding, the first breakthrough in modern genetic engineering came in 1972 when Boyer and Cohen successfully transferred DNA into E.coli bacteria using plasmid fragments. The first major medical breakthrough came in 1976 when bacteria were modified to produce somatostatin, followed 2 years later with the game changer; bacteria modified to produce insulin.
The first GM crops were a virus-resistant strain of tobacco produced in China in 1992. followed shortly thereafter by the much maligned Flavr Savr tomato. In an effort to combat a shortage of vitamin A in diets, which was estimated to kill 670,000 children each year at the time, Golden Rice was developed, eventually going on to win a 2015 Patent for Humanity award for making the world a better place.
What is CRISPR?
CRISPR stands for Clustered Regularly Interspaced Short Pallindromic Repeats, which refers to the unique organization of short, partially palindromic repeated DNA sequences found in the genome of bacteria and archaea. The technique was first discovered in Strep bacteria, which use CRISPR as a defense against viruses.
CRISPR works by targeting an extremely small section of DNA (as few as 12 base pairs) and cutting it at a precise point. The cell then uses a matching piece of DNA as a template for repairing the cut, which is possible due to the fact that humans carry DNA from both our parents. What makes CRISPR different from other genome modification techniques is the ability to insert new information into the DNA sequence.
According to Livescience:
'CRISPR technology was adapted from the natural defense mechanisms of bacteria and archaea (the domain of single-celled microorganisms). These organisms use CRISPR-derived RNA and various Cas proteins, including Cas9, to foil attacks by viruses and other foreign bodies. They do so primarily by chopping up and destroying the DNA of a foreign invader. When these components are transferred into other, more complex, organisms, it allows for the manipulation of genes, or "editing".'
Potential medical applications of the process include the correction of genetic defects (like Cystic Fibrosis and hypertrophic cardiomyopathy), elimination of allergies, disease treatment and prevention of viruses, including HIV.
So what’s Cas9?
Cas9 is an RNA-guided DNA endonuclease enzyme, which means that it’s a protein integral to the CRISPR process. Cas9 is the active agent that cleaves DNA, essentially acting like a tiny pair of scissors on the genome. Cas9 isn’t the only protein that can be used in the process, but it’s the most common and has become shorthand for the Cas (CRISPR associated) range of proteins.
That sounds… complex
Actually, this method of Genome editing is far simpler and cost efficient than previous methods. This is not to say that you’ll be using CRISPR in your kitchen any time soon, but if you have access to a fully stocked laboratory and some PHD qualified researchers, you’re all set.
The biggest potential for CRISPR in its current form is in scientific research. The highly targeted nature of the process means that researchers can disable viruses or edit specific genes to change one aspect of an organism to protect against changing environmental conditions or infection.
Another highly touted potential of CRISPR would be the eradication of the global mosquito population, which would have an immense impact of the overall health of the human race.
The World Health Organization states:
'Of all disease-transmitting insects, the mosquito is the greatest menace, spreading malaria, dengue and yellow fever, which together are responsible for several million deaths and hundreds of millions of cases every year….Malaria is endemic in 91 countries, with about 40% of the world's population at risk. By undermining the health and working capacity of hundreds of millions, it is closely linked to poverty and stunts social and economic development.'
Last, but by no means least, CRISPR has the potential to increase crop yields and reduce the need for pesticide use by introducing naturally resistant traits into the seed line. As the global population increases, many commentators argue that an extensive genetic modification program will be necessary to avoid widespread starvation.
What about Designer Babies? I’d like a tall one with blue eyes, please
Don’t hold your breath. While selecting favourable genetic traits may be theoretically possible in the long term, we are a long way from designer babies, according to the The Conversation:
'Beyond the regulatory barriers, we are a long way from having the scientific knowledge necessary to design our children. While the Oregon experiment focused on a single gene correction to inherited diseases, there are few human traits that are controlled by one gene. Anything that involves multiple genes or a gene/environment interaction will be less amenable to this type of engineering. Most characteristics we might be interested in designing – such as intelligence, personality, athletic or artistic or musical ability – are much more complex.'
The other problem is that of unintended mutations.
Wait, what’s that about unintended mutations?
Researchers led by Shoukhrat Mitalipov in Portland, Oregon recently announced a breakthrough in the modification of a human embryo using CRISPR, avoiding many of the mosaicism problems that occurred in previous experiments by making the modifications as early as possible in the foetal development process. While these embryos were not allowed to go to term (and likely will never be allowed to based on current U.S. regulations), this didn’t stop other potential issues emerging.
Said Genome Biology:
'An unintended consequence, however, is that sgRNA can introduce double-stranded breaks at non-targeted sites within the genome. The potential for these off-target effects are well known; thus, procedures are in place to reduce their frequency, screen for their occurrence, and in the case of sexually reproducing organisms, perform outcrossings for their exclusion from lines with the desired mutation.'
So, while there are procedures that can reduce unintended mutations, the process is still far from foolproof. This is part of the reason that the U.S. and other Western governments are moving cautiously on CRISPR advances, potentially slowing the pace of scientific progress. Fortunately (depending on your perspective) the boffins in China are embracing CRISPR wholeheartedly, with at least 20 human trials scheduled to take place in 2017.
I’d like to explain CRISPR to my kids/mother/boss, but I’m still struggling…
I think Neville might be able to help with that.
Unless you’re one of those people who think that any form of genetic modification is "playing god", it’s hard not to see the potential benefits of CRISPR. From the elimination of genetic conditions to the ability to cure viruses and create crops resistant to pests, CRISPR could well become one of the most important tools available to the human race.
Of course, much of this is dependent on scientists working together and governments encouraging research, two factors that are far from guaranteed. CRISPR is currently the subject of a patent battle between the Broad Institute of MIT & Harvard and UC Berkeley which may further delay progress, and a number of dubious companies have sprung up online promising to let you do “CRISPR in your kitchen”.
At the end of the day, CRISPR is a tool that scientists could use to make the world a better place.
Think for yourself.
Books by John Turnbull are now available on Amazon and Kindle. There’s supernatural thriller, Damnation’s Flame; action/romance, Reaper; black comedy, City Boy; and travel guidebook, Bar Trek: Europe. Damnation's Flame by John Turnbull is also available in the IA store HERE. (Free postage!)
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Australia License
Keep up! Subscribe to IA.