The field of genetics has, without doubt, changed the scope of science forever. As we delve deeper into the human genome, the discoveries made tell us not just of the past, but what we can do in future. Many scientists are working harder than ever to put an end to genetic conditions. After all, if it’s genes that cause it, surely gene editing can help to rectify it?
As easy as it seems and as close as we are, gene editing is still surrounded by controversy which somewhat hinders progress. It could cure diseases but in the wrong hands, it could lead to a whole host of ethical issues. Before we are quick to take sides, however, it is always imperative to have the full picture.
In this book summary readers will discover:
- Natural versus deliberate genetic modification
- CRISPR – what it is and how it works
- The possible applications of gene editing
- The questions surrounding the consequences of gene editing
Key lesson one: Natural versus deliberate genetic modification
When considering the evolution of life on Earth, it all boils down to random genetic variations. These variations were sometimes advantageous and led to the survival and success of the organism. This is the process of natural selection. The ability to be able to modify genes deliberately would mean that we could evolve on our terms.
Before we jump into deliberate gene modification, it has to be pointed out that there are some cases of natural gene editing. The best example known is when a patient named Kim, who was diagnosed with WHIM syndrome in the 1960s. WHIM is a hereditary disease caused by a single change in human DNA. When Kim was observed again 40 years later, she was found to be symptom-free. This baffled her doctors and researchers decided to take a closer look at her blood cells to figure out what had happened. They found that one of her chromosomes had 35 million letters missing and that her DNA in general was not in order as expected. They concluded that Kim’s body had undergone something called chromothripsis. This happens when a chromosome explodes suddenly and the genes it carries gets rearranged. In Kim’s case when it occurred, it erased the change that caused her WHIM syndrome, effectively ridding her of it.
So, if something like chromothripsis can cure disease unintentionally, what if it was done intentionally? Scientists first started considering the possibility when they observed viruses inserting their DNA into cells and their ability to intertwine their genome in a bacterial chromosome. The first attempt came in the 1980s by Mario Capecchi and Oliver Smithies. They were successful in rewriting defective genes by using a process called homologous recombination. However, their success only occurred 0.01 per cent of the time which made it impractical. Further attempts were made by others over the next few decades and all were problematic due to the complexity of the techniques used.
Key lesson two: CRISPR – what it is and how it works
The search for a way in which genes could be modified gained new traction when a specific region of bacterial DNA was noticed. This region of DNA was found to be repeated exactly over specific intervals. They named it clustered regularly interspaced short palindromic repeats or CRISPR for short. In the spaces between these repeats are lines of DNA called spacer sequences. These spacers sequences caught the attention of scientists when they noticed they matched the DNA found in bacterial viruses. It was then that they realized the true function of CRISPRs – they are an important part of the bacterial immune response to viruses.
The CRISPRs in bacteria store replicas of viral DNA in their spacer sequences thus equipping them for future viral attacks. The bacteria can react readily when it recognizes a viral infection. It is able to do this by implementing three things. Firstly, CRISPR-associated genes or CAS genes which codes for a protein called Cas9 that cuts and disables viral DNA. Secondly, CRISPR RNA guides the Cas9 protein to where it needs to cut and lastly tracrRNA assists to activate the process. Now, because CRISPRs function this way in bacteria, scientists began to question if it would be possible for them to target and cut DNA other than viral DNA.
When the Cas9 protein does its work to cut the DNA, scientists have a small window whereby they can insert a different piece of DNA. Thus, CRISPRs can function as a gene-editing tool. It was first demonstrated in 2012 by the author when she sliced jellyfish DNA at precise locations. The success of this study led the scientific community to embark on a whole new direction, filled with possibility. Harvard professor, Kiran Musunuru used the technique on the DNA of sickle cell anaemia patients. He was able to correct the single-letter mutation which causes the disease successfully in his lab. This quickly launched CRISPR based research into a fast-developing field as its application in the medical field could be extremely valuable.
Key lesson three: The possible applications of gene editing
The possible applications of using CRISPR as a gene-editing tool was now endless. Scientists came up with many situations where it could be used. The most practical use would be in agriculture where crops could be edited to produce higher yields, or be more resilient to extreme weather and pests. The citrus industry, for example, could benefit immensely if CRISPR was used to rid the industry of yellow dragon disease which is a bacterial plant disease. Another possibility could be in producing healthier food. Just consider soybean oil. It is highly popular but extremely unhealthy due to the high levels of trans fats it contains. With CRISPR, it would be possible to alter the soybean genes so that it contains less fatty acids and will be far more healthier for all those who consume it.
CRISPR has also been successfully used on livestock as well. Researchers in Canada have produced a pig that contains a gene from E. coli. This bacterial gene improves the pig’s digestion and reduces the phosphorus content of its manure by 75 per cent. Can you imagine how this would impact our environment if applied to all livestock?
Then, there are applications in the medical world. Most genetic diseases are caused by a single mutation of a gene. That means a one-letter spelling mistake most of the time within the gene. Many medical trials are now looking at gene therapy as the way to proceed and CRISPR could be the answer. Even people living with HIV, which is not a genetic disease but a virus, could benefit from the use of CRISPR. Some people have a natural resistance to HIV as a result of a mutation in one of their genes. If CRISPR were to be used to insert this altered gene into others, it is technically possible to prevent HIV infection from occurring. Another clear application of CRISPR in the medical world would be its use in cancer patients. Cancer is, after all, caused by mutations in DNA either inherited or acquired through environmental factors. CRISPR has the potential to delete these mutations as a treatment option or as a preventative step.
Thus, CRISPR as a gene-editing tool could be applied to many different sectors. It has the potential to make the world better for everyone by improving health, improving the environment and providing healthier food.
Key lesson four: The questions surrounding the consequences of gene editing
Despite the benefits that CRISPR can provide to us, there are also other factors to consider. Unfortunately, for every potential good that CRISPR can achieve there are individuals who will look to exploit it for financial gain. One of the authors was approached by an entrepreneur who was looking to start a company in the future that would offer people, CRISPR babies. The thought of a designer baby is a bit too much but we also live in a world where some people might be very happy with the idea. A child guaranteed not to have any diseases? Or what about hair colour, eye colour, height and gender?
The author obviously declined this request as she found it reminiscent of Hitler’s superior race but what it did make her realise is that maybe CRISPR was a bit too easy and affordable to use. There would be a slew of ethical questions that need to be answered. This resulted in experts in the field releasing a paper regarding the ethical implications of the technology and what it would mean for both the scientific community and society. They urged other researchers to hold back on work regarding the human germline until all the applications have been discussed, information gathered and boundaries are established.
It is a touchy subject for everyone involved. On one hand, you can understand the need to hold back on research on human embryos but on the other, it potentially delays all research. The author mentions that safety, ethics and regulation are the three things that have to be considered. In terms of safety, germline editing has to be deemed safe enough for clinical use. But, given the circumstances, sooner or later, governments will realise that the benefits outweigh any dangers. When it comes to ethics, the previous dilemma about the designer babies come into play. Genetic enhancements outside of improving health must be prohibited but not at the detriment of all other work. This brings us to the final point, regulations. Governments must play an active role in supervising the methods used in gene editing, however, globally, there should be a consensus amongst people about how regulations are applied.
The key takeaway from A Crack in Creation is:
CRISPR has provided scientists with an easy and surprisingly affordable way in which to edit genes. Even though the possible applications of this technology is immense, numerous ethical considerations come into play. The question now remains is whether we should use this technology to make our lives better or should we leave it be in fear of what could happen if it were not regulated properly.
How can I implement the lessons learned in A Crack in Creation:
Now that you have a brief idea of what CRISPR is and what it could possibly do, why not delve deeper and get more information about how it would help society. Then when the time comes for decisions to be made, you will already have the background knowledge required.
