A recent discovery has upset the conventional wisdom about diseases such as obesity and diabetes. Explanations.

British and Canadian researchers have just highlight a discovery that revolutionized ideas about the innate and acquired: the lives of children, including poverty, seem to influence the programming of DNA causing diseases such as obesity and diabetes in adulthood. Decryption.

The weight of the home environment

As molecular biology has taught us in recent years, the functioning of our body is governed by the products of a certain stock of genes under the control of a set of “switches”, which according to the program development, activate or deactivate genes. The study published by the “International Journal of Epidemiology” goes even further by demonstrating for the first time a link between socioeconomic factors from early life and the biochemistry of DNA .

Bringing together researchers from McGill University in Montreal, University of British Columbia in Vancouver and the Institute of Child Health at University College London, the team studied the DNA of a cohort of forty people aged 40 to 45 years followed since birth. They were in this way possible to know their background and accurately determine if their living conditions were precarious or favored. The researchers were interested in an epigenetic modification such as methylation, chemical process that usually inactive gene expression. For example, when a tumor suppressor gene is silenced by altering its DNA, this results in the appearance of a tumor.


“This is the first time a link is established between the economic conditions of childhood and the biochemistry of DNA,” said Moshe Szyf, a professor of pharmacology at McGill. “If we consider the genome as a series of sentences, the DNA, the letters, is transmitted by parents. Methylation of DNA is comparable to the punctuation that determine how the letters should be combined to form sentences and paragraphs read differently by different organs of the body, heart, brain and so on, “said Moshe Szyf. “We learned that these punctuation marks are responsive to signals from the environment, and they are marked by the living conditions in childhood. Essentially, they act as a mechanism that allows DNA to adapt to rapidly changing world. ”

A DNA according to the programmed environment

For scientists, there is a growing body of evidence to admit that the enzymatic machinery creating and perpetuating these methylation patterns, is sensitive to environmental changes during fetal life and after birth. But, says the researcher as “DNA is old and does not always fit the kind of world in which we live.” The study found that the diseases of poverty experienced in early childhood are mainly coronary heart disease, type 2 diabetes and respiratory disorders.

For researchers , this discovery is fundamental : the model that prevailed previously predicted that any epigenetic modification could take place only during pregnancy and not during the rest of life. However, it is increasingly accepted that DNA methylation, as in this study in response to the social environment, impacts the genome throughout life. If such changes in response to the environment were demonstrated in cells of the germline (eggs, sperm) then acquired characteristics are passed on to future generations , just as well.