we were discussing this phenomenon earlier.
Usually flu viruses mutate frequently and rarely will you ever find
two flu-viruses from different years where large portions of the genome
coincide.
But there are some striking exceptions. One with the Canadian swine,
where a large portion survived more than 20! years.
One other example with Korean swine, the Chinese retracted swine-sequences(?)
the Mongolian Camel and now[[http://www.recombinomics.com/News/10050603/H5N1_Recombination_Confirmation.html|this}} one.
Could it be, that the viruses don’t mutate during replication but rather
when they are folded and that some regions just aren’t available
for mutations due to the 3d-structure ?
sorry for the bad link.
this should be better.\\\\
seehere for a list of highly preserved genes over several years
Or there are mechanisms (which we don’t know of yet) to actively select out mutations efficiently.
Could be, or it could be that there is an efficient error-checking mechanism or two. A related virus, hsv (salivary)is known to have an error-checking mechanism. And of course, dual infections and recombination are a form of error checking, too. It’s very significant that most mutations are in the silent third position—that means that errors don’t last long, for whatever reason. I think folding has a lot to do with it, but there is evidence that the transfer RNA copying occurs while the strand is folded—the folds just relax a bit as the copier moves along. Some viruses open flat to copy, but influenza doesn’t seem to use that method. It seems likely to me that there is more chance for recombination to occur when copying is going on on the exposed part of the folded area.
let’s ignore recombination for a moment. Let’s assume -and there is some evidence- that some flu-viruses can replicate very accurately over many years in some large contiguous areas of the genome. Then we might ask whether mutations during replication make any sense at all ? The mutations can happen at other occasions to ensure evolution. I mean, when it can be accurate, why shouldn’t it always be accurate ?
where is monotreme ?
sequences from 1997 from China, withheld for 9 years,
areas without mutation over 7 years, recombination
see also this thread
anonymous,
Did you read this paper? Avian Influenza Virus Exhibits Rapid Evolutionary Dynamics, Rubing Chen1 and Edward C. Holmes1,.
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