It is well known that countless characteristics are inherited from parents due to the 23 chromosomes they provide to generate the cell that will develop life. For example, temperament is received and, in some cases, certain chromosomal variability that culminates in a syndrome. But science studies the possibility that it is memories that pass from one generation to another.
Epigenetics is a discipline that puts the topic on the playing field. It is the study of heritable changes in DNA and histones, which modify the structure and condensation of chromatin, affecting genetic expression and phenotype. In other words, chromosomal variability and its manifestation in the individual.
Nature magazine published a where research carried out by Bryan Dias and Kerry Ressler (Atlanta University, Georgia) is presented in which the initial question was whether the life of ancestors, their vices or their participation in war, would have clear effects on subsequent generations.
Dias spent hours experimenting with mice and observed how the fear associated with a smell can affect the animals and leave a mark.
He exposed male mice to acetophenone (a sweet-smelling chemical used to make fragrances) after lightly tapping their feet. The animals were exposed to this process five times a day for three days. The result was that they began to be afraid of acetophenone even without receiving the blow.
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The researcher allowed the rodents to mate with healthy females. Their offspring turned out to be especially sensitive to acetophenone. The same thing happened with his grandchildren. The environmental information was inherited.
It is now known as Transgenerational Epigenetic Inheritance. Traumatic experiences are recorded in the DNA and, when reproduced, can affect the central nervous system of the children.
The topic is still controversial and there have been responses to such research. Even the same journal proposes that one of the reasons why skepticism continues is that the mechanism by which this inheritance would be functional is still mysterious and that a deep dive into reproductive biology is required to demonstrate how the relevant signals can be formed. in the germ line.
“Our results provide a framework to address how environmental information can be inherited transgenerationally at the behavioral, neuroanatomical and epigenetic levels,” the researchers in their report.
Epigenetics was born in the 90s from the question: Is there a connection between the chemical reactions that regulate gene expression and the mechanisms by which memories are installed in memory? Its pioneers are the neurologist Michael Meaney and the geneticist Moshe Szyf. It is intended to explain that certain traits can be inherited without modifying the DNA.
The plants too
The natural selection It is not a primitive thing, living beings face dangers every day that make them acquire defensive traits, such as that of plants against herbivorous animals (thorns are a clear example). However, there are “memories” in plants that have been partially consumed by animals, which is why they generate an induction of chemical defense when they see danger lurking again. Generating that the consumer sees the quality of their intake reduced, which invites them to withdraw.
The phenomenon is called “Priming” or “punching” and has a resemblance, although superficial, to the improvement of animals’ defenses against pathogens after having had an experience with them.
In his article ““, the Sevillian biologist Carlos M. Herrera explains what he calls Defensive Memory. He proposes that plants have “epigenetic marks” due to DNA methylation (which controls the expression and regulation of genes), which are inherited and passed unaltered from mother to child.
It means that the defense against danger can be transmitted to its descendants without them having to suffer an attack, before being able to defend themselves against phytophages.
Jung and the collective unconscious
The Swiss psychiatrist Carl Jung (1875-1961), proposed the existence of a collective unconscious, shared from person to person by inheritance rather than personal experience. Therefore, the inherited content is similar even if two individuals face different experiences in life and at different stages of history. The shape is symbolic and the raw material is known as archetype (Cloninger, 2003).
Jung dreamed at the time of a deep place inside a two-level house, in turn within that place he discovered a deeper place, in which there were broken vessels and a lot of dust (elements that meant remains of a culture). primitive). He also discovered two very old, semi-destroyed human skulls (Cloninger, 2003).
The psychiatrist interpreted this eventuality as a structural diagram of the human soul that we all carry regardless of culture (Cloninger, 2003).
Jung discovered similarities between the experiences of his psychotic patients and the symbols of art and mythology in the ancient era, for example (Cloninger, 2003).
In other words, the psychiatrist determined that the collective unconscious, It unconsciously shapes us by the remote experiences of the human species and is transmitted through genetic inheritance.
After all, a bird that has grown up in isolation will make a nest without anyone showing it when it is about to hatch.
Epigenetics still has a long way to go, and although it has not determined whether an event experienced by ancestors can be fully remembered, it sheds light on the fact that, at least, the responses to stimuli established in previous generations can appear the same in their decendents.
On the other hand, humanity shares symbolism, such as the dragon in China or the feathered serpent in Mesoamerica, or as the universal archetype of the mother figure. All this can be a memory, perhaps universal, as Jung said.
The inheritances are still there, deciding, unconsciously, for us.
References:
Cloninger, S. (2003). Theories of Personality (Third Edition ed.). Mexico: Pearson Education. Prentice-Hall.
Dias B., Ressler, K. (),
Herrera, C. (2014),