We are all the same, yet we are all different. With the participation of researcher Josefa Antón, from the University of Alicante's Department of Physiology, Genetics and Microbiology, a new study has shown how a family of tiny viruses lives in the guts of humans around the world, yet changes depending on which country we are from.
The study, published in the prestigious journal Nature Microbiology, is a global collaboration with more than 115 scientists drawn from 65 countries on six continents. The team found that a common virus called crAssphage exists in sewage from over one-third of the countries of the world.
"This work is an example of collaborative science, where all researchers provided virus sequences from the whole world in order to understand the origins of our microbiome, an essential part of who we are, and how it changes over time," said Dr. Antón. "CrAssphage is a natural and crucial element for a balanced gut microbiota," she pointed out.
CrAssphage is a powerful indicator of fecal pollution and human impacts. It may one day help scientists manipulate the gut microbiome by targeting harmful bacteria. "Knowing how it works paves the way for new lines of research to eliminate bacteria that are harmful to humans," Dr. Antón added.
Co-leader, Assistant Professor Bas Dutilh from the Utrecht University in the Netherlands, has a hypothesis as to why this virus is so widespread. "CrAssphage does not seem to have any direct benefit, for example to our health. But we found closely related viruses in fecal samples from gorillas, monkeys, and other wild primates. Based on these results, we think that it has evolved with us for millions of years, and spread with humans across the globe. This is the first time anyone has shown that human gut viruses can be at least as old as the human lineage."
Project leader, Professor Robert Edwards from San Diego State University in California, USA said "We are in debt to all the amazing colleagues around the world who helped us explore the global diversity of this unique virus. This is truly a world-first in the global scope and nature of the project."
UA researcher Josefa Antón concluded "It was a rewarding experience to be a part of this consortium designed to investigate the little-known crAssphage virus." The study would not have been possible without help from the University of Alicante, whose Molecular Microbian Ecology Laboratory obtained DNA sequences from crAssphage found in Alicante's sewage, thus providing key data to support the analysis.
Edwards, R.A. et al. (2019 Global phylogeography and ancient evolution of the widespread human gut virus crAssphage. Nature Microbiology. doi.org/10.1038/s41564-019-0494-6.