The genome sequence of an RNA virus population clusters around a consensus or average sequence, but each genome is different. A rare genome with a particular mutation may survive a selection event, and the mutation will then be found in all progeny genomes. The selection process is illustrated in this diagram: The diagram on the …
Until the late 1970s the diversity of viral populations was not widely appreciated. The first study to quantitatively describe viral diversity employed the RNA bacteriophage Q-beta. The authors made a startling conclusion based on their analysis of variation within stocks of the virus: A Q-beta phage population is in a dynamic equilibrium with viral mutants …
Now that we have examined influenza viral RNA synthesis, it’s a good time to step back and look at a very important property of this step in viral replication. All nucleic acid polymerases insert incorrect nucleotides during chain elongation. This misincorporation is one of the major sources of diversity that allows viral evolution to take …
On episode #31 of the podcast “This Week in Virology”, Vincent, Dick, Alan, and Marc Pelletier summarize the past week’s influenza H1N1 activity, and discuss parvovirus infection of dogs and humans. [powerpress url=”http://traffic.libsyn.com/twiv/TWiV031.mp3″] Click the arrow above to play, or right-click to download TWiV #31
Once the (-) strand influenza viral RNAs enter the nucleus, they serve as templates for the synthesis of mRNAs. These molecules are then transported back to the cytoplasm, where they direct the synthesis of viral proteins. However, the mRNAs are not complete copies of the viral (-) strand RNAs – they are missing sequences from …
There are some interesting statistics on influenza in the current issue of CDC’s Morbidity and Mortality Weekly Report. The first is this map showing the number of confirmed cases (N = 1,882) of novel influenza A (H1N1) virus infection worldwide as of May 6, 2009: With the exception of a few countries, the vast majority …
