The Microbes Inside Us
The fact that a significant portion of the DNA in the human body comes from bacteria has been recognized for some time. Although there have been overstated statements about the magnitude of it—some have even incorrectly asserted that more than 90% of it is made up of bacteria—we have just recently learned that the actual ratio of human cells to germs in our bodies is somewhere around 1.3:1. Even if that could be unexpected in and of itself, the situation becomes much stranger as we learn more about it.
A new study found that the bacteria that make up our body are much more diverse than previously believed, and that around 99% of them are absolutely foreign to us. These don't match any of the microbial species we are aware of on Earth in our genomic databases, and we would need to create totally new classifications to even catalog them.
Furthermore, we are also unsure of the precise functions that these bacteria perform within the body. We have theories and educated guesses as to why newborns who are unable to support a diverse colony of gut bacteria at birth experience several health issues as they age.
