DNA is not everything

I have an image in mind that can be easily found online: by making a palm print on a support that provides nourishment to microorganisms, a population of varied microbes is highlighted. In addition to being a reminder to wash your hands, it is a representative image of how we coexist with many other species of living beings!

Beyond the dirty hands of a child playing in the park, the human body is crowded with billions of microorganisms, such as bacteria, viruses and fungi. They are found everywhere, on the skin, in the mucous membranes of the mouth and respiratory tract, in the intestine. And, very importantly, they help carry out important functions, such as digestive, metabolic or immune functions, essential for our health! All these tenants of our organism are so strongly connected with our vital functions, that we can no longer consider ourselves as autonomous and distinct entities!

A study recently published in Science proposes this radical change of perspective, useful for a more complete study of living organisms. To describe this situation we speak of “microbiome”: the set of genetic heritage and environmental interactions of all microorganisms in a defined environment. In this perspective, every complex organism, whether a human, a plant or an animal, must be seen as an aggregation of host cells and a vast community of microorganisms, which live in close interaction and synergy.

This new perspective highlights the importance of considering these close interactions to understand more completely the life of organisms, their health and the onset of diseases. In particular, identifying and clarifying the value of these interactions can help us better understand the growth, biological functions, response to stress or resistance to diseases of host organisms.
If in 2000 the conquest was that of having the entire human genome available, with the possibility of identifying defects and variations as the cause of diseases or predisposition to certain pathologies, after twenty years a piece is added to this paradigm and the view is broadened again. Scientists highlight how this new perspective helps us address the problem of missing heredity: sometimes studying only an individual's DNA does not make it possible to explain some of their complex characteristics.

This study strongly highlights the interdependence between complex organisms and simple organisms, from a scientific point of view and by analyzing quantifiable aspects. We can go much further by thinking about the interdependence with our peers and how much this can impact our lives, in terms of health and well-being. But that's a whole other story!

Valentina Turinetto
NP December 2024