Annalisa Marotta, Department of Epidemiology and Prevention, I.R.C.C.S. Neuromed
Each of us has a specific genetic makeup, inherited from our parents, unchanged over time. But our phenotype, how we are in appearance and in our functions, is subject to changes resulting from the interaction of genes with the environment in which we are born and we grow, which translates into a variable gene expression, resulting in the so-called phenotype.
For many years it was thought that different genetic makeups interacted in a distinct way with the environment to generate different phenotypes. This axiom seems to falter in its absoluteness when we read the results of a study conducted by a group of Canadian researchers from Ontario Institute for Cancer Research and University of Montreal, recently published in the journal Nature Communications.
Canadian researchers enrolled 1007 subjects living in three different regions of Quebec (two urbanized and one rural). By characterizing their genetic makeup, it was possible to distinguish native inhabitants of each of the three regions from those who arrived there with migratory flows.
With great surprise, researchers could not associate the genetic distinctions with the different gene expressions observed. Participants’ phenotypes seemed to be influenced for the most part by the place in which they live, i.e. the environment. As a result, individuals with distinct genetic profiles end up having the same pattern of expression if they share the same living environment.
In addition to this discovery, Canadian researchers have also been able to specify some of the environmental elements that most determine these changes. In particular, twelve pollutants, some socio-economic indexes and anthropometric factors were taken into consideration. The authors found that sulfur dioxide influences the expression of 170 genes having regulatory function on cardio-metabolic and respiratory processes. Again, these changes do not depend on the genetic diversity of individuals, but on the environment in which they live.
Future studies on epigenetics will be necessary to confirm these results and to evaluate the potential impact on health and disease prevention.
Favé, M.J., Lamaze, F.C., Soave, D., Hodgkinson, A., Gauvin, H., Bruat, V., Grenier, J.C., Gbeha, E., Skead, K., Smargiassi, A. and Johnson, M., 2018. Gene-by-environment interactions in urban populations modulate risk phenotypes. Nature communications, 9(1), p.827.