On April 25, 1953, James Watson and Francis Crick published a paper in Nature magazine teaching for the first time the double helix structure of DNA. What Can A DNA Test Really Say About You (Part I).
The finding, which would not have been possible without the contributions of Rosalind Franklin and Maurice Wilkins, forever changed the history of science.
The importance of their discovery is still celebrated today with the commemoration of DNA Day.
Sixty-six years after the presentation in society of the double helix of our genetic material, research on DNA continues.
In the 1970s, recombinant DNA technology was developed that enabled the generation of genetically modified organisms, and in the early 21st century, the Human Ge
In the 1970s, recombinant DNA technology was developed that enabled the generation of genetically modified organisms, and in the early 21st century, the Human Genome Project was completed. nome Project was completed.
These advances have leapt in recent years from laboratories to real life.
With the advent of personalized medicine, it is increasingly common for patients to see their genome sequenced in order to individualize treatments, an approach that is already possible, for example, in the fight against breast cancer.
Today, it is also possible to buy a DNA test from companies that offer these services directly to consumers. But how reliable are these types of genetic tests?
What is DNA and what does it determine?
DNA is the molecule that carries our genetic information, that is, the instructions that largely determine a person’s characteristics.
Our genetic material, which is found inside cells, serves as the code for making proteins, components that have great importance in different biological functions.
If there is a life-long error in the DNA or, on the contrary, the genetic material already contained a flaw, which we call mutation, it can increase the risk of certain diseases.
Many physical traits are also determined by the instructions coded in the DNA, although the most recent studies indicate that everything is more complex than we had initially thought.
For example, in the past, scientists thought that the color of the eyes depended on a single gene. Further research has shown that eye colour is directly determined by the degree and type of iris pigmentation, and that it is influenced by multiple genetic factors.
It is not the only myth that exists about the impact of genetics on a wide variety of physical traits.
John McDonald, Professor of Biology at the University of Delaware, developed a comprehensive guide to the rumors and false beliefs that still exist about human genetics.
For example, it is not true that characteristics such as cheek dimples, earlobes, or the ability to roll the tongue are determined by a single gene.
Therefore, it is also not possible to perform a DNA test that shows, with the analysis of a single marker, whether or not we have dimples, what our earlobes look like or whether or not we can do things with the tongue.
The traits of a person, as well as the predisposition to suffer a disease, can be written in the genetic information of an individual. However, this information is extremely complex to analyze and interpret.
Right-handed or Left-handed
To give another example, while previously it was believed that being right-handed or left-handed was determined by a single gene, today we know that up to forty different genes can influence this characteristic.
Other aspects, such as intelligence, hair shape or even the appearance of gray hairs are also influenced by our genetics, although it is not the only factor that acts on a person’s characteristics and traits.
Some scientists are currently developing tests known as “DNA photography”. The methodology, however, is still in its initial stages.
In other words, physical traits are determined by many more genetic factors than was previously thought, and genetic tests can only predict these traits, without giving information that is completely conclusive.
On the other hand, the results obtained from DNA should also not be considered definitive since not everything is written in our genetic material.
The expression of our genes, i.e. whether they are “on” or “off”, depends on switches called epigenetic markers.
Depending on environmental conditions, for example, it is possible that a gene may or may not be activated.
Therefore, having a specific DNA sequence may not be fully determinant if epigenetic switches turn off their expression.
What are Genetic Tests and what can we Learn?
Genetic tests or DNA tests are a series of tests that are performed in the laboratory to study the instructions for our genetic material.
Thanks to them, for example, it is possible to diagnose diseases, identify changes in DNA that cause a pathology already detected, determine the severity of a disorder or advise on the best therapy that is feasible to administer.
This type of tests are generally carried out in clinical practice, so that specialized sequencing and bioinformatics units advise doctors and patients to carry them out.
There are also other types of genetic tests that are marketed directly to the consumer.
Companies offer a series of panels to their clients, so that they study the presence or absence of specific markers, which could be related to a greater predisposition to suffer a disease.
Recently, the U.S. Food and Drug Administration authorized the company 23andMe to sell this type of DNA test, changing the criteria that had been maintained since 2013, when the agency determined that there was not enough evidence to commercialize these tests on DNA.
This type of genetic testing can give us some clues about the risk of suffering from a certain pathology. However, environmental conditions, socioeconomic factors and lifestyle play a key role in our health.
Therefore, the information we can obtain from these DNA tests is not definitive, and should only encourage us to change habits that could be harmful.
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