Genetic determinism: what it is and what it implies in science

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

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

Starting from 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 was even argued that there was no possible way to change these characteristics, because the genes were above practically any environmental factor. This was what ultimately led to some of the worst episodes in modern history.

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

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Genetic determinism: are we our DNA?

Genetic determinism, also called biological determinism, is the set of beliefs whose common idea is the defense that human behavior depends largely on the genes that have been inherited. This opinion also defends the idea that the environment hardly exerts any influence on the behavior or way of being of the person.

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

Genetic determinists considered that genetics was what explained all or most of how people are and that environmental and social factors have little influence on the way of being of humans. This type of thinking came to defend the needlessness of educating or carrying out therapeutic processes because, if the person she was less intelligent or had a disorder because there was a tendency in his family for it, why fight the genetics? If it has to manifest itself, it will manifest itself.

By reducing everything that humans are to simple genetic explanations, the environment in which the most advantaged and the most disadvantaged people had developed was often ignored. A tall person who has lived in an environment in which there has not been any type of lack of food is not the same as a shorter person 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.

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Genetic determinism and how it has influenced modern history

These are some examples of the way in which genetic determinism has been embodied in theories and ways of understanding the world in general.

August Weismann and germplasm

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

this biologist He was the first to propose the existence of a substance in which hereditary characteristics were found. and that it was behind how a living being was genetically configured: the germinal plasm.

The primitive idea of ​​germinal plasm was the antecedent of what we know today as deoxyribonucleic acid or DNA. The idea behind the germinal plasm was that in it were the genes, which controlled what the organism was like.

Weismann He held that the material present in the germ cells could not be modified during the life of the organism.. This idea clashed with the idea of ​​Lamarkism, which held that the events that occurred in the life of a individual that implied changes for the organism would also be transmitted to the generation later.

Genetic reductionism and social Darwinism

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

It should be said that Darwin never intended that his ideas about evolution be distorted and misinterpreted as they were. did those who used Darwinian evolutionary principles to explain the characteristics of the population.

The idea behind social Darwinism is that of genetic reductionism, which consists of defending that aspects so complexes such as personality or suffering a certain type of psychological disorder are caused by just one or two genes. According to this vision, a person who has inherited only one gene considered maladaptive will manifest the unwanted behavior yes or yes.

Starting from genetic reductionism, social Darwinism defended that the differences between races, genders, ethnic groups and social classes are they were undoubtedly due to having inherited bad genes and, therefore, applying discriminatory measures taking into account this was totally justifiable.

As a consequence of these beliefs, one of the first measures that defended social Darwinism were the eugenic laws, applied in various places in Europe and North America from the decade of the 20s and 30s of the last century.

The eugenics movement maintained that both physical negative traits, such as having motor disabilities, and psychological ones, such as suffering schizophrenia or low intellectual performance, had a genetic basis and, to prevent their spread, those who manifested them had to be prevented from becoming reproduced.

If people with bad genes were prevented from having offspring, these genes would not be passed on to the next generation, and maladaptive traits would thus be exterminated. In this way, thousands of people were sterilized in the United States. These same eugenic laws were taken to the extreme in Nazi Germany., being 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 but considered misfits, such as homosexuals and people antifascists.

Not everything is genetic, and not everything is environment: epigenetics

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

When the Human Genome Project revealed in 2003 that there were actually only 30,000 genes in the human species, scientists were somewhat confused. Human beings barely have 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.

From this, the idea was raised that it was not really all genes. That there was something else that influenced the production of such a high amount of proteins, some 100,000, 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 his biological mother. However, whether these genes are manifested or not 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.

Gene-environment interaction has been called epigenetic. and it is an aspect that in recent years has been gaining much importance, especially in the field of health. Being able to influence what the person has genetically inherited was apparently not as impossible as believed.

This finding completely contradicts the defenders of genetic determinism because, if well they are right that the genes will continue to be in each and every one of the cells of a individual, the environment influences whether or not they will be activated and cause the person to behave in a certain way or suffer from a specific disease.

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

Thus, the genetic material makes us have a tendency to manifest a specific type of cancer, to have a specific type of particular personality or being physically slender, to name a few examples, but it does not limit you to being it. 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, today, in the field of hereditary and genomic science, the idea is defended that half of how we are 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.

Bibliographic references:

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