Genetic determinism: what is it and what does it imply in science?

Genetic (or biological) determinism has influenced the development of science for many years.

In the last hundred years, important discoveries have been made in the field of biology that have allowed us to understand how our physical and psychological characteristics are more similar to those of our parents than to those of other people.

Genetics has been extending its field of knowledge, especially since Mendel made his first experiments on how traits were inherited and, also, when Rosalind Franklin and company discovered that DNA was the molecule that contained the genes.

Based on the idea that we are what we have inherited, there were many, both scientists and politicians, who defended the idea that our behavior and physical characteristics depend entirely on our genes. This is what has been called genetic determinism.. It came to be argued that there was no possible way to change these characteristics, because genes were above practically any environmental factor. This is what eventually led to some of the worst episodes in modern history.

Let's take a closer look at the belief behind genetic determinism and how it has been applied throughout the 21st century.

Genetic determinism: are we our DNA?

Genetic determinism, also called Biological determinism, is the set of beliefs whose common idea is that we are our DNA. the set of beliefs whose common idea is the defense that human behavior depends mostly on the genes we have inherited.. This opinion also defends the idea that the environment has little influence on the behavior or the way of being of the person.

Thus, if a person is the daughter of tall and intelligent parents, by inheriting the genes behind these characteristics, he or she will undoubtedly present them. In turn, in the case of having parents with some type of mental illness or disorder, there will be a risk of inheriting the genes that may be behind these ailments and, according to genetic determinism, these problems will inevitably manifest themselves.

Genetic determinists considered that genetics explained all or most of what people are like, and that environmental and social factors barely and that environmental and social factors have little or no influence on the way humans are. This type of thinking came to defend the unnecessary need to educate or carry out therapeutic processes because, if the person was less intelligent or suffered from a disorder because there was a certain tendency to it in his or her family, why fight genetics? If it has to manifest itself, it will manifest itself.

By reducing everything that the human being is to simple genetic explanations, the environment in which the most favored and the most disadvantaged people have developed was often ignored. A tall person who has lived in an environment where there has been no lack of food is not the same as a person of smaller stature who has suffered from malnutrition. This example, although simple, serves as an explanation that, sometimes, the environment can be much more decisive than genetics itself.

Genetic determinism and how it has influenced modern history.

Here are some examples of how genetic determinism has influenced modern history. examples of the way in which genetic determinism has been embodied in theories and ways of understanding the world in general. and ways of understanding the world in general.

August Weismann and the germ plasm

In 1892, the Austrian biologist August Weismann proposed the idea that multicellular organisms, such as humans and other animals, have two types of cells: somatic cells and germ cells. Somatic cells are responsible for the basic functions of the organism, such as metabolism, while germ cells are responsible for transmitting hereditary information.

This biologist was the first to propose the existence of a substance in which the hereditary characteristics were found and which was behind how a being and which was behind how a living being was genetically configured: the germ plasm.

The primitive idea of germ plasm was the ancestor of what we know today as deoxyribonucleic acid or DNA. The idea behind germ plasm was that it contained genes, which controlled what the organism was like.

Weismann held that the material present in germ cells could not be modified during the life of the organism.. This idea clashed with the idea of Lamarkism, which held that events occurring in the life of an individual that involved changes to the organism would also be transmitted to the subsequent generation.

Genetic reductionism and social Darwinism

With the passage of time, mixing August Weismann's own ideas with the thoughts on evolution expounded by Charles Darwin in The Origin of Species (1859), the idea of social Darwinism emerged, defended by Darwin's cousin, Francis Galton.

It must be said that Darwin never intended his ideas on evolution to be misrepresented and misinterpreted as those who used Darwinian evolutionary principles to explain population characteristics did.

The idea behind social Darwinism is that of genetic reductionism, which consists of defending that aspects as complex as personality or suffering a certain type of psychological disorder are caused by just one or two genes. According to this view, a person who has inherited only one gene considered not very adaptive will manifest undesired behavior..

Based on genetic reductionism, Social Darwinism argued that the differences between races, genders, ethnic groups and social classes were undoubtedly due to having inherited bad genes and, therefore, applying discriminatory measures taking this into account was totally justifiable.

As a consequence of these beliefs, one of the first measures advocated by Social Darwinism was eugenic laws.The eugenics movement, applied in various parts of Europe and North America starting in the 1920s and 1930s.

The eugenics movement held that negative traits, both physical, such as having motor disabilities, and psychological, such as suffering from schizophrenia or low intellectual performance, had a genetic basis and, in order to prevent their propagation, those who manifested them should be prevented from reproducing.

If people with bad genes were prevented from having offspring, these genes would not be passed on to the next generation and, thus, the maladaptive characteristics would be exterminated. In this way, thousands of people in the United States were sterilized. These same eugenic laws were taken to the extreme in Nazi Germany.This was applied in the form of mass extermination of people who, according to the prevailing racism, were inferior to the Aryan race: Jews, Poles, Gypsies, as well as non-ethnic groups considered to be misfits, such as homosexuals and anti-fascists.

Not all is genetics, not all is environment: epigenetics

In recent years, human beings have been trying to find out how many genes they have. Until relatively recently, it was argued that humans must have about 100,000 genes. The reason for this was that approximately the same number of proteins was found in the human species and, taking into account the scientific principle (now rejected) that for each gene a particular protein is produced, there should be that many genes in our species.

When the Human Genome Project revealed in 2003 that the human species actually had a total of only 30,000 genes, scientists were somewhat confused. Humans have barely more genes than mice or houseflies.. This finding was surprising because it was somewhat shocking to discover that a species as apparently complex as ours had a relatively low number of genes.

This led to the idea that it was not really all about genes. That there was something else that influenced the production of such a high number of proteins, some 100,000, while having so few genes, barely 30,000.

It is true that a person has a specific genetic configuration, the result of having inherited the genes of his biological father and mother. However, whether or not these genes manifest themselves may depend on certain environmental and even social factors.. The genotype of each person is that genetic configuration, but the phenotype is what actually manifests itself.

The gene-environment interaction has been called epigenetics and is an aspect that has been gaining importance in recent years, especially in the field of health. and it is an aspect that has been gaining importance in recent years, especially in the field of health. Being able to influence what a person has inherited genetically was apparently not as impossible as previously thought.

This finding completely contradicts the advocates of genetic determinism because, while they are right that genes will still be in each and every cell of an individual, the environment influences whether they are activated or not, the environment influences whether or not they will be activated and cause the person to behave in a particular way or suffer from a particular disease..

One demonstration of this has been the discovery of the phenomenon of methylation, in which, either by having a particular type of diet, or by living in an environment where the air is cleaner or more polluted, certain genes are modified by the incorporation of a methyl group, without the need for genetic engineering.

Thus, genetic material makes us have a tendency to manifest a particular type of cancer, have a particular type of personality or be physically slender, to give a few examples, but it does not limit you to be that. Between 10 and 15% of human diseases are hereditary, in the rest it is possible to modulate their effects by carrying out healthy habits.

It could be said that nowadays, in the field of hereditary and genomic science, the idea that half of what we are like is determined by the 25,000 genes that each one of us possesses, while the other half is determined by our social, dietary and climatic environment.

Bibliographical references:

• Esteller-Badosa, M. (2017) I am not my DNA. The origin of diseases and how to prevent them. RBA LIBROS. Spain.
• Velázquez-Jordana, J. l. (2009). Freedom and genetic determinism. Praxis filosófica, 29, 7-16.