Researchers have uncovered a suite of bacteriophages that Live Science says "blur the line between living and nonliving."
University of California, Berkeley's Jillian Banfield and her colleagues collected metagenomic datasets from a range of sources, including animal fecal samples, hot springs, marine ecosystems, and more, to reconstruct 351 phage genomes, six plasmid-like sequences, and four sequences of unknown classifications. As they further report in Nature, the researchers note that these phage have large genomes that are more than than 200 kilobases in length — with one reaching 735 kb in size — with expanded genetic repertoires. These expanded repertoires included new CRISPR-Cas systems, new tRNAs and related machinery, and ribosomal proteins.
"Typically, what separates life from nonlife is to have ribosomes and the ability to do translation; that is one of the major defining features that separate viruses and bacteria, nonlife and life," co-first author Rohan Sachdeva from UC Berkeley says in a statement. "Some large phages have a lot of this translational machinery, so they are blurring the line a bit."