Scientific and technological objectives of the project and state of the art

RNA viruses as a threat to humanity

High throughput (HTP) DNA sequencing has led to the extensive accumulation of data. However, despite the fact that the first genome sequences of RNA viruses were available early on, because of a lack of concerted effort, genomic sequence information of RNA viruses now lags behind that obtained for other organisms. This is in part due to the difficulty and the cost of working on these often highly dangerous infectious agents that requires containment safety conditions, only found in P3 or P4 laboratories. Moreover, the massive and automated shotgun strategy used for large DNA genomes does not apply to short genomes such as found in RNA viruses.

To date, according to the International Committee on Taxonomy of Viruses, more than 350 species of viruses that possess an RNA genome and can infect vertebrates have been described (not including retroviruses and viruses from fish). However, the genomes of only 30% of these have been sequenced. An equivalent number of putative new species remains to be classified and sequenced. Recent history has shown that most emerging viral pathogens (Hepatitis C virus, Dengue/West-Nile viruses, Ebola virus, Nipah and Hendrah viruses, SARS coronavirus (SARS-CoV), etc.) belong to RNA viruses. This is a consequence of their huge genetic diversity and propensity for rapid evolution.

It is widely accepted that our knowledge of viral evolution is directly linked to the amount of genomic data available for analysis. In particular, complete genome analysis has revealed discontinuous evolutionary events such as recombination and reassortment that may play a major role in RNA virus diversity, virulence and host specificity.