The researchers found that Yanomami people harbor microbiomes with the highest diversity of bacteria and genetic functions ever reported in a human group. That tells us that Western diets and lifestyles have a great impact on our microbiomes.
Back in labs in the U.S. (at Mount Sinai, New York University, University of Colorado, Boulder and others), researchers sequenced DNA isolated from the Yanomami samples. From this, they were able to identify all of the bacterial species that make up the skin, mouth and gut microbiomes of people who had never been exposed to Western diets, antibiotics or other environmental factors that make up life in industrialized societies. The researchers then compared these non-Westernized microbiomes to the microbiomes of people living in Western society and people living in villages in the midst of transition from isolation to urban lifestyles.
Each collective house or village considers itself an autonomous economic and political entity (kami theri yamaki, ‘we co-residents’) and its members ideally prefer to marry inside this community of kin with a ‘cross’ cousin, that is the son or daughter of a maternal uncle or paternal aunt. This type of marriage is reproduced as far as possible between the families in a generation and from generation to generation, making the collective Yanomami house or village a dense and comfortable mesh of consanguine and affinal bonds.