We have all seen, at least once, a movie where they talk about the modification of organisms, even humans, to enhance certain characteristics such as stature, strength, speed, and even to make them more attractive. However, something that is not mentioned is how this process occurs.
About ten years ago, the winners of the Nobel Prize in Chemistry 2020, Jennifer A. Doudna and Emmanuelle Charpentier established the use of "molecular scissors" to make certain changes in our DNA so precisely that what we once saw as science fiction is now a reality.
Modifications through history
Our human nature always leads us to know more, to see beyond what we are currently living. Since our ancestors became sedentary and began to practice agriculture and livestock raising, they noticed that, if they made certain crosses with animals or plants that had desirable characteristics, they obtained a product with better characteristics. For example, in plants, the fruits are better tasting, resistant to climatic factors, better yields, among other traits.
But as we have already mentioned, humans have always sought ways to make things faster and more efficient, so they began to conduct experiments with the technology they had at the time. Sometimes they subjected plants to ultraviolet radiation, which generated changes that were often favorable, but sometimes not. The desire to improve organisms to date has not stopped.
According to data from the 2020 FAO (Food and Agriculture Organization of the United Nations), the first modified foods were on sale in the early 1990s, such products were: soybeans, cotton, corn, papayas, and potatoes. These modifications have been made mainly by the novel methods of transgenesis, which means that new genes are inserted or the expression of existing ones is modified.
We now consume some of these food products, such as tomatoes that have a longer shelf life, corn that has resistance to pests, or even the insulin required by diabetics, which is now produced in modified cell reactors, when previously it was obtained from the pancreas of animals. Research is currently underway in various laboratories to obtain modified organisms using gene editing methods utilizing molecular scissors, which will lead to obtaining microorganisms, plants, and animals with new and interesting characteristics.
What does this gene-editing technique consist of?
Before talking about this type of technique and everything that can be done with it, we must first know what DNA is. At the end of the 1960s, a Swiss biochemist, Fredrich Miescher, discovered the DNA molecule, a milestone in the research of all living organisms. DNA is the basis of life and consists of a language of four compounds called nucleotides: adenine (A), thymine (T), cytosine (C), and guanine (G), which together form a long chain coiled like a snail-shaped ladder, is composed of two strands and to form it, the nucleotides interact in pairs: A with T and G with C.
These compounds are the key to determining your entire genetic makeup such as eye and skin color, height, even if you are prone to develop some kind of disease, etc. An important aspect to note is that these same four nucleotides are found in all living organisms, from bacteria to larger organisms such as plants and animals, hence the importance of knowing how they behave and what we can improve.
Now, what began as research on the defense mechanism of bacteria against virus-generated infections -specifically the so-called bacteriophages, and how through this mechanism they manage to survive this battle-, ended up being "the technique" in terms of DNA editing. Since the discovery of DNA, many scientists have searched for ways to achieve the cleanest and most precise editing, which had not been achieved until a few years ago using the technique that emerged from this research: CRISPR/Cas.
What does this mean?
Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) stands for Clustered Regularly Interspaced Short Palindromic Repeats; while the acronym Cas stands for CRISPR Associated System, which groups together a set of proteins, mostly nucleases, responsible for cutting (s) at a specific DNA site. In particular, with CRISPR/Cas9, a gene sequence is edited by the activity of Cas9 endonuclease, which identifies a palindromic sequence of nucleotides that are fragments that are read equally from left to right or right to left.
Cutting DNA precisely makes it easier to insert new sequences, change nucleotides, remove fragments, and, in general, do precise genetic engineering. It is worth mentioning that DNA cannot be broken, as it can cause damage, even death, but nature is so perfect that it has developed a repair mechanism that consists of reattaching these broken sections.
The CRISPR-Cas9 technique gained prominence because of its precision and low cost. Anyone with a properly equipped laboratory can perform it, which seems to be true, since according to a review article conducted two years after the discovery, there were at least a thousand articles where the acronym CRISPR was found in the title or abstract.
Medical implications and the ethics of human modification
The new CRISPR technology promises to be an alternative to diseases that afflict us today such as cancer and those caused by viruses such as the recent COVID-19 pandemic. Gene editing can, in theory, be performed on human cells to develop gene therapies to help control chronic diseases such as cancer or even modify DNA to eliminate syndromes such as Down's syndrome. Although CRISPR-Cas9 technology is novel, it heralds the beginning of a new era in which once it is used on a large scale (plants, insects, and bacteria) or in humans, there is no turning back.
In the case of humans, the idea of designer babies generates controversy and perhaps will continue for years to come, are we ready to talk about genetically modified people? Probably not, even with the potential of the CRISPR technique, we are still making mistakes, unwanted mutations are still occurring, and the risk is still high. Although the technology is there and in theory we can do it, who will regulate this? Will it have to be banned? Who will have access to this technology? The picture is complex and as a society, we have a huge challenge in front of us.
This is projected to occur in the distant future; however, I believe it is an issue that should not go unnoticed. We must take into account that many years ago, those who discovered fire saw that they could cook their food and keep warm, although it was also used as a tool to cause harm.
So it happens with this technology, it has advantages and disadvantages, but it will always be better to know the process, as it is not right to err on the side of false innocence. The more we know about it, the more we will be able to regulate it and know what is being done.
This new technology is here to stay and will change humanity as we know it and time will tell to what level. At the moment, it is not considered ethical to use it on people. At present, the legislation does not contemplate a specific regulation for this scope; Mexican norms are focused on the regulation of transgenics in agricultural and food production and on health and environmental issues.
However, since 1997, the United Nations Educational, Scientific and Cultural Organization (UNESCO) has pronounced itself in favor of improving the health of individuals but stresses that the dignity of individuals must be respected, as well as prohibiting discrimination based on genetic characteristics. Nevertheless, nothing assures us that in the future it may be unethical for people not to have access to this type of technology.
Written by Genesis García Téllez, Source: Saber Más magazine publishes popular science articles in a digital format (web).