Recently, researches have determined that it is not genetics, but the environment that shapes the formation of a microbiome will impact disease onset and progression.

What does this mean?

Eran Segal, a computer scientist and computational biologist at the Weizmann Institute of Science, and his colleagues went to Israel to conduct their investigation into where diseases truly come from. They chose Israel because of its genetically diverse population of Jewish people. In collecting blood and stool samples from over 1,000 Israeli adults from different backgrounds (i.e. Ashkenazi, North African, Yemenite, Sephardi, and Middle Eastern descent), researchers compared the different genetic profiles and ß-diversity of the microbiome samples of said adults. The results were shocking: genetics determined a “very small fraction of the variability that is seen across the microbiomes of people.”

To further prove the degree of which the environment influences the microbiome, Segal and his colleagues examined the microbiome compositions of related individuals, who never lived in the same household, and unrelated individuals, who lived together. The results showed that those who were unrelated and lived together had similar microbiomes, while those who were genetically related’s, but did not live in the same environment, microbiomes were different.

Why is this important?

Segal’s research proves that although some bacteria in the microbiome is heritable, they make up a small percent of the microbiome. Segal and his colleagues wanted to take their research one step further, and examine if host phenotypes can be predicted from microbiome composition. Instead of only using genetic data to predict a phenotype, researchers used both genetic and environmental factors, which gave them a more accurate prediction of a human phenotype.

For example, in a small study, they discovered that the microbiome contributed to 36 percent of the variation between people’s HDL cholesterol levels and 25 percent of the variation in their body mass indices. So maybe high cholesterol does not run in the family?

This study is very important in figuring out the most efficient way to fight diseases. It is vital to know which bacteria are not heritable, so that doctors can use the composition of microbiome to determine how to treat an illness. I believe that the combination of the microbiome, environmental factors, and genetics is key to understanding a disease, and knowing how to treat it. Since it has been discovered that environmental factors play a huge role in forming the gut microbiome, I am curious if scientists will use this information to control the environmental factors surrounding an infant, and see if that impacts any diseases said infant comes in contact with during its lifetime.



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