Multicellular organisms’ genetic evolution has occurred in response to environmental difficulties such as nutritional competition, climatic change, physical and chemical stresses, and infections. However, an organism’s fitness is determined not just by its capacity to defend itself, but also by its ability to exploit symbiotic creatures. Indeed, bacteria not only contain pathogenicity, but also allow for effective nutrition absorption from nondegradable diets. Furthermore, microorganisms play critical functions in the establishment of host immunity. The study examines interactions between microorganisms and host immunity with correlations between particular host genes and variation in microbiota composition. Recent genome-wide association analyses indicate that the exquisite outcome of genetic coevolution is symbiosis between host and bacteria. Furthermore, a subset of microorganisms from the human and mouse microbiota have been found to interact with humoral and cellular immunity. Surprisingly, microorganisms linked to both host genetics and host immunology are taxonomically related. Bifidobacterium, Lactobacillus, and Akkermansia are the most involved, as they are linked to both host immunity and host genetics.

Researchers conclude that future therapies targeting microbiota in chronic inflammatory disorders must take into account both immunological and genetic host characteristics associated with microbiota homeostasis.