We explain what genetic manipulation is, its advantages, disadvantages and ethical aspects. Also, examples today.
What is genetic manipulation?
It is known as genetic manipulation or genetic engineering to the different techniques and scientific-technological procedures that allow humans to modify or recombine DNA and other nucleic acids from living beings, with the purpose of obtaining life forms that satisfy certain needs. To do this, genes are added, altered or eliminated from the genetic code of living beings, also called genetic editing.
The human alteration of the genetic content of living beings has been taking place since the beginning of civilization. Through processes such as domestication and selective breeding, humans applied artificial selection to the fate of different breeds of dogs, livestock or food plants.
However, these are considered indirect forms of genetic alteration, very different from those available in a laboratory thanks to biochemistry and genetics, whose intervention on the genome is direct.
Direct genetic manipulation had its origins in the 20th century, thanks to advances in biochemistry and genetics, but specifically to the discovery in 1968 of restriction enzymes (restriction endonuclease), a type of protein capable of recognizing specific segments of the genetic code and “cutting” DNA at a certain point .
This finding by the Swiss biochemist Werner Arber (1929-) was later developed and refined by the Americans Hamilton Smith (1931-) and Daniel Nathans (1928-1999).
Thanks to this, in 1973 the American biochemists Stanley N. Cohen and Herbert W. Boyer took the first historical step in the genetic manipulation of an individual: they cut a DNA molecule into pieces, recombined the pieces and later injected it into a bacterium. escherichia coli, which proceeded to reproduce normally.
Today there are various genetic engineering techniques, such as DNA amplification, sequencing and recombination, the polymerase chain reaction (PCR), plasmacytosis, molecular cloning or gene blocking, among others. Thus, it is possible to alter specific segments or specific substances in the deep biochemical functioning of a living being, being able to “program” it to perform tasks or provide it with certain characteristics.
Obviously, this type of knowledge involves an important ethical dilemma, since the alterations introduced to the genome are then inherited to the offspring of living beings and therefore they endure in the species.
Genetic engineering can achieve plant species more resistant to pests, for example, or mice with congenital diseases for medical experimentation, or even therapies for incurable diseases; but also to design diseases for an eventual bacteriological warfare.
Types of genetic manipulation
The main forms of genetic manipulation today are the following:
- DNA sequencing. It is about the application of different biochemical methods and techniques to the DNA molecule of a living being, in order to determine what is the specific sequence of nucleotides (Adenine, Guanine, Thymine and Cytosine) that composes it, something key to decipher the ” natural programming ”of biochemical processes that take place during life. DNA sequencing is a colossal task, since it involves immense amounts of information, even in the case of microscopic beings, but today it can be carried out quickly thanks to computerization.
- Recombinant DNA. This technique consists of the generation of an artificial DNA molecule through methods in vitro, and then inject it into an organism and evaluate its performance. This is generally carried out by extracting certain information from a living being and incorporating it into another, and allows obtaining specific proteins (for medical or pharmacological purposes), obtaining vaccines, or improving the economic performance of food species.
- The Polymerase Chain Reaction (PCR). Also called PCR, for its acronym in English, it is a DNA amplification technique developed in 1986, which consists of obtaining numerous copies of a DNA “template” molecule, from a series of enzymes called polymerases. This method is currently used in very different areas, such as DNA identification in forensic investigations, or the genetic identification of pathogens (viruses and bacteria) of new diseases.
- The CRISPR. His name is an acronym in English (clustered regularly interspaced short palindromic repeats) of grouped and regularly interspaced short palindromic repeats, which is the name of the ability of bacteria to incorporate into their genome part of the DNA of the viruses that have infected them, inheriting from their descendants the ability to recognize the invading DNA and be able to defend themselves on future occasions. In other words, it is part of the immune system of prokaryotes. But since 2013 this mechanism has been used as a means of genetic manipulation, taking advantage of the method by which bacteria “cut” and “stick” their own DNA to incorporate new information, using an enzyme called Cas9.
Examples of genetic manipulation
Some examples of the application of genetic engineering today are:
- Gene therapy. Used in the fight against genetic diseases, this type of therapy consists of replacing a defective segment of individuals’ DNA with a healthy copy, thus preventing congenital diseases from developing.
- The artificial obtaining of proteins. The pharmaceutical industry obtains many of its proteins and substances for medical use thanks to the genetic alteration of bacteria and yeasts (fungi), such as Saccharomyces cerevisiae. These living things are genetically “programmed” to produce huge amounts of organic compounds, such as human chitinase or human proinsulin.
- Obtaining “improved” animal species. In order to combat hunger or simply to maximize the production of certain plant or animal foods, the genome of cattle, pigs or even edible fish has been altered, to make them give more milk or simply grow faster.
- The seeds of “transgenic” food. In a similar way to the previous one, fruit, vegetable or vegetable plants have been genetically altered in order to make them more profitable and maximize their production: crops that better withstand drought, that defend themselves against pests, that produce larger or larger fruits. with fewer seeds, or simply fruits that mature more slowly and therefore enjoy a longer period to be transported to the consumer without being damaged.
- Obtaining recombinant vaccines. Many current vaccines, such as the one that protects us from hepatitis B, are obtained through genetic manipulation techniques, in which the genetic content of the pathogen is altered to hinder or prevent its reproduction, so that they cannot produce the disease, but they can allow the immune system to build up defenses against future actual infections. This also makes it possible to isolate specific genes to inject into the human body and thus acquire immunity against various diseases.
Advantages and disadvantages of genetic manipulation
As we have seen, genetic engineering enables previously unthinkable tasks to be carried out, thanks to a deep understanding of the key mechanisms of life. Thus, we can point out among their advantage:
- Massive and rapid obtaining of essential biochemical substances, capable of fighting disease and improving the health of humanity. This applies to both drugs, vaccines and other compounds.
- The possibility of significantly improve the food industry and to combat hunger and malnutrition in the world, through crops that are more resistant to the climate or that produce larger and more nutritious fruits.
- The opportunity to “Correct” genetic defects that cause disease through point gene editing.
However, among his disadvantages they find each other:
- They involve ethical and moral dilemmas that force to rethink the place of the human being in the order of things, since an error in genetic manipulation can ruin an entire species or produce an ecological disaster.
- “Improved” species compete with advantage over natural species, so that they begin to replace them, impoverishing the genetic variety of the species, since, for example, the same improved seeds are used for crops in different world geographies.
- The long-term effect is unknown of the intake of genetically manipulated foods in the human population, so there could be complications later on that are still unforeseeable.
Ethical aspects of genetic manipulation
Like all scientific exercises, genetic manipulation is amoral, that is, it has both beneficial and possibly harmful powers, depending on how we use them. This implies a necessary ethical debate regarding the intervention of human beings in nature at such deep and irreversible levels, which are transmitted over time from one generation to another.
One of these dilemmas has to do with the limits of human interference in the biological functioning of species. Should the welfare of humanity or, worse still, the welfare of the food industry or the world capitalist system, be above the welfare of animal or plant species? Is it worth impoverishing the genetic legacy of the only known planet alive, to produce more profitable crops?
To this must be added the possibility of give rise, consciously or accidentally, to new species of living beings, especially of microorganisms. How sure are we that we are not building pathogens capable of causing worldwide suffering, not only to human beings, but to other species?
Lastly, there is the human aspect. How much should we intervene in our own genome as a species? Treating diseases and birth defects is a laudable goal, but one that deserves a careful look, since it is dangerously close to the “improvement” of the species.
The latter could bring numerous future inconveniences, from unpredictable diseases that are passed down to generations to come, to societies based on genetic discrimination, as science fiction has warned on numerous occasions.
Legal aspects of genetic manipulation
Having understood the ethical dilemma that genetic engineering represents, it is understandable that there is the need for a specific legal framework on the matterthat ensures not only environmental defense, but also the dignity of human life, present and future.
Most of these legal and ethical codes seek to draw the line that separates the therapeutic – the fight against diseases and the fight to improve people’s quality of life – from the ideological, aesthetic or political. Obviously, these legal provisions vary according to the legal framework of each country.
However, actions such as human cloning, the introduction of heritable traits in the genome and direct treatment of the embryo for purposes other than strictly medical purposes, are prohibited and are considered immoral and risky for humanity, in accordance with the provisions of the Universal Declaration on the human genome and human rights (UN), and by the International Bioethics Committee of UNESCO.
Even so, there are voices that demand that these multilateral organizations make a stronger and more explicit statement on the matter, especially after the first two human twin girls were born in China in 2012 free of all risk of HIV virus infection, thanks to the application -totally illegal- of the CRISPR method in their embryos. That is, the first two people genetically edited.