Genetic Manipulation

We explain what genetic manipulation is, its advantages, disadvantages and ethical aspects. Also, examples today.

What is genetic manipulation?

The different techniques and techniques are known as genetic manipulation or genetic engineering. scientific-technological procedures that allow humans to modify or recombine DNA and other nucleic acids of living beings, with the purpose of obtaining life forms that satisfy certain needs. To do this, genes are added, altered or deleted from the genetic code of living beings, also called genetic editing.

Human alteration of the genetic content of living beings has been occurring since the beginning of civilization. Through processes such as domestication and selective crossing, 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 the advance of biochemistry and genetics, but specifically to the discovery in 1968 of restriction enzymes (restriction endonuclease), a type of proteins capable of recognizing specific segments of the genetic code and “cutting” the DNA at a certain point .

This discovery by the Swiss biochemist Werner Arber (1929-) was later developed and perfected 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 historic step in the genetic manipulation of an individual: they cut a DNA molecule into pieces, recombined the pieces and subsequently injected it into a bacteria. escherichia coliwhich proceeded to play normally.

Today there are various genetic engineering techniques, such as DNA amplification, sequencing and recombination, 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 entails an important ethical dilemma, since The alterations introduced to the genome are then inherited to the offspring of living beings and therefore they persist in the species.

Genetic engineering can achieve plant species that are 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 war.

Types of genetic manipulation

The main forms of genetic manipulation today are the following:

• DNA sequencing. It is the application of different biochemical methods and techniques to the DNA molecule of a living being, in order to determine the specific sequence of nucleotides (Adenine, Guanine, Thymine and Cytosine) that composes it, something key to deciphering the “ “natural programming” of the 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 vitroto then inject it into an organism and evaluate its performance. This is generally carried out by extracting certain information from one living being and incorporating it into another, and allows the obtaining of specific proteins (for medical or pharmacological purposes), the obtaining of vaccines, or the improvement of 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 “template” DNA molecule, from a series of enzymes called polymerases. This method is currently used in very different areas, such as the identification of DNA in forensic investigations, or the genetic identification of pathogens (viruses and bacteria) of new diseases.
• CRISPR. Its name is an acronym in English (clustered regularly interspaced short palindromic repeats) of short palindromic repeats grouped and regularly interspaced, which is what is called the ability of bacteria to incorporate into their genome part of the DNA of the viruses that have infected them, inheriting to their descendants the ability to recognize the invading DNA and be capable of defending themselves on future occasions. That is, 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 “paste” 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 the individuals' DNA with a healthy copy, thus preventing congenital diseases from developing.
• 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 beings are genetically “programmed” to produce enormous quantities of organic compounds, such as human chitinase or human proinsulin.
• Obtaining “improved” animal species. With the purpose of fighting hunger or simply maximizing 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.
• “Transgenic” food seeds. 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 tolerate drought better, that defend themselves against pests, that produce larger fruits or with fewer seeds, or simply fruits that mature more slowly and therefore have 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 can allow the immune system to prepare defenses against future real 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 makes it possible to carry out previously unthinkable tasks, thanks to a deep understanding of the key mechanisms of life. Thus, we can point out among its advantages:

• The massive and rapid obtaining of essential biochemical substances capable of combating diseases and improving the health of humanity. This applies to drugs, vaccines and other compounds.
• The possibility of significantly improve the food industry and combat hunger and malnutrition in the world, through crops that are more climatically resistant or that produce more nutritious and larger fruits.
• The opportunity to “correct” genetic defects that cause diseases through specific genetic editing.

However, among his disadvantages are found:

• involve ethical and moral dilemmas that force us 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 an advantage over natural species so 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.
• Long-term effect unknown of the ingestion of genetically manipulated foods in the human population, so there could be still unforeseeable complications later on.

Ethical aspects of genetic manipulation

Like any scientific exercise, genetic manipulation is amoral, that is, it has both beneficial and possibly harmful powers, depending on the use we give them. This implies a necessary ethical debate regarding human intervention in nature at such deep and irreversible levels that 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 well-being of humanity or, even worse, the well-being of the food industry or the global capitalist system, come before the well-being of animal or plant species? Is it worth impoverishing the genetic legacy of the only known planet with life, 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 microorganisms. How sure are we that we are not building pathogens capable of causing global suffering, not only to humans, but to other species?

Finally, there is the human aspect. How much should we intervene in our own genome as a species? Treating diseases and congenital defects is a laudable objective, but one that deserves a careful look, since is dangerously close to the “improvement” of the species.

The latter could bring numerous future problems, from unpredictable diseases that are inherited to future generations, to societies based on genetic discrimination, as science fiction has warned on numerous occasions.

Legal aspects of genetic manipulation

Once the ethical dilemma that genetic engineering represents is understood, it is understandable that there is the need for a specific legal framework on the matter which 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 characters into the genome and direct treatment on the embryo for purposes other than strictly medical ones, 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 UNESCO International Bioethics Committee.

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 infection with the HIV virus, thanks to the application – totally illegal – of the CRISPR method in their embryos. That is, the first two genetically edited people.

Continue with: Transgenic organisms

References

• “Genetic engineering” on Wikipedia.
• “Genetic manipulation” at UBA HOY of the University of Buenos Aires (Argentina).
• “Genetic engineering” at the National Human Genome Research Institute (USA).
• “Redesigning life: what are the limits of genetic manipulation” by Luciana Mantero in La Nación (Argentina).
• “Universal Declaration on the human genome and human rights” in the Office of the High Commissioner for Human Rights of the United Nations.
• “The birth of genetically edited twin girls is announced amid scientific skepticism” in El Independiente (Spain).
• “Genetic engineering” in The Encyclopaedia Britannica.