Host Genotype and the Effect on Microbial Communities

TLDR: The microbial ecosystems found along the body surfaces of mammals have provided a variety of complementary metabolic functions to their hosts, and there are several indications that host genotype is an important factor affecting the diversity and function of the microbiota.

Abstract: The microbial ecosystems found along the body surfaces of mammals have provided a variety of complementary metabolic functions to their hosts. It is likely that the mammalian host and its microbiota form a coalition of cells, or a so-called “super-organism,” which mutually strives for survival. Unfortunately, the exact interactions between host and microbiota are for the most part unexplored. Our current understanding of host–microbe interactions mostly comes from studies on the gastrointestinal tract microbiota, which is the most densely populated microbial ecosystem of the mammalian host. Although mammalian host genes are greatly outnumbered by the total gene pool of their microbiota, there are several indications that host genotype is an important factor affecting the diversity and function of the microbiota. Communication between host cells and microbes is likely to be dependent on host-immune system-related genes and can therefore be influenced by polymorphisms in these genes. However, there are probably more genes which are important for host–microbe interactions that are not directly related to the immune system. Future studies should focus on the hierarchy in importance of host genotypes with relation to host–microbe interactions. Complicating the studies on host–microbe interactions are environmental factors, which can sometimes drastically influence both the host and its microbiota. Especially dietary influences should be taken into account while analyzing the interaction between the microbial communities of the gut and the host.