Genetics and behavior: do genes decide how we act?

A summary to understand how our genes influence our daily actions.

The human body is the result of millions of years of evolution of the material found in the nucleus of cells: DNA. Genes are the units of information contained in this genetic material.The translation of the genetic code is expressed in characteristics, whether physical (the color of the eyes, the type of hair or the shape of the nose) or psychological (behavior or personality).

But does everything depend on genes alone? In other words, are we what we are and how we behave? are we who we are and do we behave the way we do because our DNA tells us to be that way? The answer is no. The environment around us has something to say about that. Human nature is very complicated, but we are getting closer to understanding it every day.

Genetically based behavior

The use of twins for studies has been a great tool that scientists have been using for years to understand how genes and environment influence individuals differently. The idea is to look at the extent to which it is nurture or genes that serve to better predict the regularities that can be found in the organism's development and repertoire of habitual behaviors.

Twin research shows strong evidence of when and how genes and environment shape human nature. Some of it reveals that the importance of genes can change dramatically depending on the stage of life we are in. Genetic influence tends to increase over the years in many traits, as has been seen with theas has been seen with body weight.

In another area, twin research has been important in the field of molecular genetics. The best known is with body weight. Thanks to these kinds of studies, it has been possible to identify almost 100 genetic variants involved in obesity.

But the effect of genes need not be limited to how our bodies are formed; It also explains how certain psychological predispositions appear in our bodies.. For example, it is believed that we make choices in search of an environment that favors our predisposition to express genetically inherited strengths. A teenager who is genetically good at reading is likely to start going to a library in search of more books, where he will meet like-minded people and may begin to relate to them.

Similarly, IQ is largely heritable and it is difficult to change it in a significant and sustained way through exercise and new learning.

Fear of genetic determinism

Twin studies are a great opportunity to understand when the environment has more power over us and when behavior is easier to shape.

However, in the field of psychology and cognitive science, they have become embroiled in controversy.. Critics of twin research question whether psychological characteristics, such as mental health, have a strong genetic basis. This is partly due to a fear of the idea that everything we think, feel and do is little more than the consequence of genes doing their job and condemning us to a life we cannot change.

However, this fear is unfounded.

Genes are not everything

The influence that genetics has on human characteristics is often misunderstood.. It is wrong to assume that behavior that has a strong genetic influence must be innate by obligation. Genes are not everything; a gene will express itself depending on the environment, that is to say, it can show its effects or have none at all, depending on the environment in which we live.

An example will make it clearer. There are people who are predisposed to lung Cancer because of their genetics. Unless they smoke or breathe tobacco smoke constantly, it is very likely that they will not develop the disease. And the same is being seen with behavior. Behavior is elicited as a response to an environmental cue..

Although some forms of behavior have a genetic basis, this does not imply that this predisposition will cause our brains to be designed in such a way that we manifest these behaviors regardless of how we interact with the environment. Although our DNA cannot be modified through experiences and learning, the expression or not of its genes depends largely on the environmental conditions in which we live. For example, studies in relation to schizophrenia (a mental illness with a strongly heritable component through genes) show that the expression of the disease is greater when living in a context that produces stress.

Does knowing the genetic basis imply danger?

One of the fears generated by this work is that, by recognizing that behavior has a genetic basis, people will no longer be equally responsible when it comes to committing themselves to healthy behaviors and to the education of their children.

However, knowing one's predisposition to mental or other illnesses need not lead to a loss of interest in health improvement; on the contrary, gain a commitment and motivation to change their behavior and habits.