The human gut microbiome is a complex microbial ecosystem composed of trillions of bacteria, archaea, viruses, and fungi that has coevolved with humans over millions of years. This long-term evolutionary association has played a fundamental role in human digestion, nutrient absorption, immune system development, metabolism, and even the maturation of the nervous system. Many researchers now regard the human body as a holobiont, in which the host and its associated microbiome together constitute an integrated evolutionary unit. This prolonged coevolutionary relationship has been particularly important in shaping the human immune system. Beneficial gut microorganisms educate and regulate immune responses, enhance resistance against pathogens, and contribute to the control of inflammation. However, in the modern era, excessive antibiotic use, heightened hygiene practices, urbanization, and profound dietary changes have partially disrupted this coevolved relationship. Accumulating evidence suggests that such disruption is associated with an increased risk of allergies, inflammatory bowel disease, obesity, type 2 diabetes, and other chronic disorders. Collectively, the human gut microbiome is far more than a community of commensal microorganisms; it is an integral component of human evolution. Understanding the coevolution of humans and their gut microbiome is therefore essential for elucidating the mechanisms underlying long-term health, physiological adaptation, and the future trajectory of human evolution.
Rashidul Haque* (Fri,) studied this question.