It’s not at all clear what these phages that infect bacteria even do:
They analyzed more than 28,000 gut microbiome samples taken from 28 countries.
This process revealed complete genomes for more than 140,000 species of viruses living in the human gut. (A single person, however, carries around only a fraction of these species.) Though many types of viruses live in the gut, they focused on viruses that can infect bacteria, called “bacteriophages” or “phages” for short.
The researchers limited their scope to bacteriophages because “we are still figuring out their role in human health,” said lead author Luis Camarillo-Guerrero, a recent PhD graduate from the Wellcome Sanger Institute in the U.K. “It’s probably safe to say that the vast majority of them are not harmful to us and are simply an integral component of our body microbiota.”Yasemin Saplakoglu, “70,000 never-before-seen viruses found in the human gut” at LiveScience
The paper is open access.
An alert reader spotted this in the paper: “After clustering the whole proteome of GPD into 202,192 protein clusters, we found that top functions corresponded to DNA binding proteins, integrases, methylases, peptidases, and tape measure proteins; however, the majority of phage proteins (47.46%) could not be assigned a function.”
The reader comments that viruses cannot afford to carry around much non-functioning nucleic acid. More likely, the 43% that are mystery proteins do have a function. If even viruses are much more complex than we expect, what chance that all these complex systems arose by natural selection acting on random mutations (Darwinism)?