Newly found small-genome viruses suggest encapsulins and viruses evolved from each other repeatedly

First author Abelardo Aguilar, a doctoral student in biology at the University of Miami, in its College of Arts and Sciences, ties the shared fold to a larger question ^[12]. "These proteins build compartments with two different roles, which connects directly with the study of the origin of life and its early evolution because if you think about it, life at its core is about enclosing reactions and also enclosing information that can be inherited so those reactions can happen in the future," he said ^[11].

That framing explains why the claim is about direction. A virus with features of both groups shows the groups are connected ^[8]. Whether it sits on a path from viruses to encapsulins, the reverse, or both is an inference from sequence and structure, and the authors read it as running both ways, repeatedly ^[6]. We'd expect a group of intermediates to test the one-way account better than a single find would, because a group lets the pattern recur or fail to.

Sequencing is what made the search possible. "The majority of viruses cannot be grown in the lab. But now through sequencing, we have access to information on viruses for which we don't know the host, that we can't culture in the lab, but that are everywhere," said Antoni Luque Santolaria, the senior author ^[3][12]. The databases held billions of DNA sequences ^[1]. The report does not say how many new viruses the search found or whether any has a known host.

Phys.org says the discovery has implications for biotechnology as well as for understanding the origins of life ^[4]. Aguilar pointed to one possibility on the shell side. "One implication of this research is the possibility that viral capsids could also facilitate biochemical reactions, which would open up the potential roles that capsids have in environments as a whole," he said ^[10].