Latest DNA survey reveals 99% of human microbes are mysterious to science


The human body is a walking ecosystem. It is home to bacteria, viruses, fungi, and other small organisms. These organisms known as microbes. The organisms form communities that make up the human microbiome. No two human microbiomes are the same, means each person not just an ecosystem, but a unique ecosystem. However, the age of microbes around more than 3.5 billion tears, means the oldest form of life on earth.

Stanford DNA survey

The new Stanford survey of DNA suggests, our bodies contain vastly more diverse microbes than anyone previously understood. Most of those microbes have never seen before.

The study is an accidental discovery, as researchers investigated less invasive ways to say whether a patient’s body would reject a transplanted organ. Rather than the completely miserable experience of having a tissue biopsy taken, the researchers studying whether a simple blood sample would suffice. Essentially, the idea was that if they found fragments of the organ donors DNA flowing in a patient’s blood. It is a good indication that the body was rejecting the transplant.

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DNA fragments

Apart from patient’s DNA fragments, the collected samples contain fragments of the organ donor’s DNA along with collection of bacteria, viruses and other microbes that reconcile a person’s microbiome. Over the course of several studies, researchers collected samples from heart, lung and bone marrow transplant recipients, along with pregnant women.

The results suggested the identifiable changes to the microbiomes of people with immune systems and that positive results for the organ donor’s DNA were a good sign of rejection.

However, the survey has found that 99 percent of microbes in the human body are completely unknown to science. The clear majority of it belonged to a phylum called Proteobacteria, which includes E. coli and Salmonella bacteria.

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Researchers said, we’ve doubled the number of known viruses in that family through this work. Importantly, they’ve found an entirely new group of torque teno viruses. Among the known torque teno viruses, one group infects humans and other infects animals, but many of the ones the researchers found didn’t fit in either group. According to researchers, the new class of human-infecting ones that are closer to the animal class than to the previously known human ones, is quite divergent on the evolutionary scale.

With many microbes living in the human body, it’s hardly surprising that science hasn’t gotten around to identifying them all.

The research team says, the next step is to apply the technique to the microbiomes of other animals to identify viruses that could potentially jump to humans and trigger outbreak diseases, like avian and swine flu.

More information: [PNAS]