Are you carrying a hand sanitizer with you always? Do you think all germs in your body are bad? Not all germs are bad. Actually, some of the bacteria in our body are good for us. The body has an ecosystem made of different kinds of bacteria. This ecological community of bacteria is called a microbiome.
High Number of Bacteria
The number of bacteria in our body is over 100 trillion, 10 times greater than the number of human cells in our body (1).
High Number of Bacterial Genes
The number of bacterial genes in our body is about 3.3 million, 100 times more than the number of human genes (about 23,000) (2).
What are the Differences Between People?
We are 99.99% identical to each other on the human gene level. This high similarity goes down to 10% when you compare the microbial DNA of each person. Therefore, the differences between each person are mainly due to the differences of microbial DNA. This tells us that we are largely influenced from the microbiome.
- Ley, Ruth E., Daniel A. Peterson, and Jeffrey I. Gordon. "Ecological and evolutionary forces shaping microbial diversity in the human intestine." Cell124.4 (2006): 837-848.
- Vyas, Usha, and Natarajan Ranganathan. "Probiotics, prebiotics, and synbiotics: gut and beyond." Gastroenterology research and practice 2012 (2012).