We know how the first months of life are decisive for the physical and mental health of a newborn. Now researchers have discovered that parental behavior can actually alter the DNA sequence in brain cells of newborns! Indeed, a group of American researchers have established a link between maternal interactions that occurred before weaning and the structure of DNA.
The experiment involved mice, but in this case they are a good animal model of the human. The researchers have shown that the DNA of the brain cells of newborns changes (until the moment of weaning), depending on the type of mothering they receive: the less they are pampered, the more it changes.
It was also already known that interactions with the environment act as genetic “switches”, activating or deactivating genes — these “functional units” of DNA that encode a trait of the body (eye colors or others). But it was unknown until now that in the period before weaning, the environment of a child can change the very structure of the DNA of his or her brain cells, that is to say the distribution and the number of genes on the DNA strand. A first!
For this study, the researchers studied two groups of mice. The first group consisted of female mice (and their offspring) whose behavior observed during the experiment was protective and caring (care, grooming, etc.). The second group gathered the mice clearly less attentive with their offspring. The researchers then demonstrated that there was an inverse correlation between the number of genes copied and stuck in the DNA of the brain cells and the degree of mothering of each female, measured on a numerical scale taking into account the time spent on grooming the babies, the mother’s attention, etc.
To be certain that this correlation was real, the researchers took precautions, notably by exchanging newborns: some born to mothers who were not very attentive were entrusted to attentive mothers and vice versa. They then found the same phenomenon, removing the possibility that the copy-bonded gene rate is a hereditary effect of parents and not a direct reaction to the environment.
If the researchers have speculated on the chain of biochemical reactions that lead to the mother’s behavior causing an effect on the jumping genes of their babies (including the methylation effect), this mechanism still needs to be researched and better explained. Nevertheless, a subsequent follow-up of the newborns showed that those who underwent numerous genetic copy-pasting were more stressed and inappropriate adults.
The workings of this mechanism need to be further clarified, but this experiment on mice could open perspectives in humans. Some psychiatric and neurological diseases such as depression and schizophrenia may be related to the genes developed before weaning and new treatments could be considered appropriately.