PubMed · 2026-05-13
Scientists discovered that giant viruses hiding inside the DNA of a marine alga can wake up, replicate, and spread — both to offspring and to neighboring cells. This overturns the idea that viral DNA buried in a host genome is just harmless genetic baggage.
Full-length, functional phaeovirus genomes were found fully integrated and transcriptionally active within the brown alga Ectocarpus host genome
Viral reactivation is triggered by specific environmental and developmental cues, including temperature shifts, demonstrating precise host-controlled regulation
Using CRISPR-Cas and classical genetics, the team confirmed these viral elements are stably inherited through the germline and can spread both vertically (to offspring) and horizontally (to neighboring cells)
