An international team of INRAE and CIRAD researchers discovered molecular fossils of viruses embedded within plant genomes [1].
This finding allows scientists to trace the evolutionary trajectory of viruses over vast geological timescales. By analyzing these genetic remnants, researchers can understand how ancient pathogens interacted with their hosts and how those relationships shaped modern plant biology.
The study sought to determine if it is possible to study the history of viruses that emerged several hundred million years ago, a researcher said [2]. To answer this, the team explored plant genomes to locate the molecular fossils of viruses [1].
These genetic signatures act as a biological archive, reflecting 300 million years of evolution [1], [2]. Because viruses mutate rapidly, traditional fossils rarely preserve their structure; however, the integration of viral sequences into the host's own DNA creates a permanent record, a molecular fossil, that persists for millions of years.
"An international team of INRAE and CIRAD researchers answered this question by exploring plant genomes to find the molecular fossils of viruses," a researcher said [1].
The discovery highlights the complex co-evolution of plants and viruses. By mapping these ancient sequences, the team can reconstruct the ancestral states of viral families and identify the mechanisms viruses used to integrate into plant genomes during the Paleozoic era.
This research provides a new framework for genomic archaeology. It suggests that other organisms may also harbor similar viral archives, which could reveal the origins of various infectious agents that continue to impact global agriculture and ecosystems today.
“Plant DNA harbors virus 'fossils' that reflect 300 million years of evolution.”
The identification of 300-million-year-old viral fossils in plant DNA transforms the understanding of viral evolution from a study of current mutations to a longitudinal historical analysis. This genomic archaeology allows scientists to identify long-term patterns of host-pathogen adaptation, potentially aiding the development of more resilient crop varieties by understanding how plants historically survived ancient viral onslaughts.
