Researchers from Portland State University in Oregon have recently discovered a new type of viral genome, reports Helen Thompson at the Nature News blog. It is a "hybrid" genome "that seems to be the product of recombination between a DNA virus and an RNA virus." The study, published recently in Biology Direct, describes this "natural chimera" that lives in Boiling Springs Lake, an acidic volcanic hot spring in California, Thompson says. The team did a metagenomic analysis of samples from the lake to get a better picture of the viruses present there. But they found something surprising, Thompson says — a piece of DNA coding for a protein that has, until now, only been found in RNA viruses. After sequencing and analyzing the rest of the viral fragments in their samples, the researchers were able to reconstruct this new virus' complete genome. "In the genome, the RNA-like sequence sat adjacent to another sequence for a replication protein that is unique to DNA viruses," Thompson adds. "The resultant single-stranded circular genome, dubbed BSL RDHV (short for Boiling Springs Lake RNA-DNA hybrid virus), seems to be the result of a recombination event between two completely unrelated virus groups." The researchers still aren't sure how the recombination happened.
Daily Scan's sister publication GenomeWeb Daily News has more on this study.