Our Gut Microbiome: The Evolving Inner Self

The “holobiont” concept, defined as the collective contribution of the eukaryotic and prokaryotic counterparts to the multicellular organism, introduces a complex definition of individuality enabling a new comprehensive view of human evolution and personalized characteristics. Here, we provide snapshots of the evolving microbial-host associations and relations during distinct milestones across the lifespan of a human being. We discuss the current knowledge of biological symbiosis between the microbiome and its host and portray the challenges in understanding these interactions and their potential effects on human physiology, including microbiome-nervous system inter-relationship and its relevance to human variation and individuality. Host-microbe associations vary and evolve during the lifespans of human beings. This review provides insights into symbiotic relationships between the microbiome and its human host in the context of physiology and aging.