‘It’s insane’: New viruslike entities found in human gut microbes

As they collect and analyze massive amounts of genetic sequences from plants, animals, and microbes, biologists keep encountering surprises, including some that may challenge the very definition of life. The latest, reported this week in a preprint, is a new kind of viruslike entity that inhabits bacteria dwelling in the human mouth and gut. These “obelisks,” as they’re called by the Stanford University team that unearthed them, have genomes seemingly composed of loops of RNA and sequences belonging to them have been found around the world. Other scientists are delighted by obelisks’ debut. “It’s insane,” says Mark Peifer, a cell and developmental biologist at the University of North Carolina at Chapel Hill. “The more we look, the more crazy things we see.” It’s not yet known whether obelisks affect human health, says Matthew Sullivan, an integrative biologist at Ohio State University, but they could alter the genetic activity of their bacterial hosts, which in turn could affect human genes. Most people know RNA, or ribonucleic acid, as DNA’s alter ego—ferrying proteinmaking recipes encoded in a DNA-based gene to molecular “kitchens” outside the cell nucleus that string together a protein’s amino acids. But more than 200 viruses, including those that cause flu, Ebola, and COVID-19, bypass DNA, having genomes composed only of RNA. Their genomes include sequences encoding the proteins that make up a viral shell and ribozymes, enzy...
Source: Science of Aging Knowledge Environment - Category: Geriatrics Source Type: research