The Evolution of Microbiomes in the Gut

Microbiomes are like fingerprints, so diverse that no two people can have identical ones. Within a population, any two randomly chosen individuals usually have less than half of their microbiome species in common. On average, the overlap in the microbial makeup of the gut is between 30% and 35%. Microbiologists debate whether there is a core set of microbial species that all healthy people have,. If it exists, it's probably a single digit percentage of the total.