Avian Influenza Virus Exhibits Rapid Evolutionary Dynamics.

[Mingus]

<dl class="PubmedArticle" id="dlPubmedArticle16945980"><dd class="abstract" id="abstract16945980">http://www.ncbi.nlm.nih.gov/entrez/..._uids=16945980&query_hl=1&itool=pubmed_docsum
</dd><dd class="abstract" id="abstract16945980">
</dd><dd class="abstract" id="abstract16945980">1: Mol Biol Evol. 2006 Aug 31; [Epub ahead of print]</dd><dd class="abstract" id="abstract16945980">Avian Influenza Virus Exhibits Rapid Evolutionary Dynamics.

• Chen R,
• Holmes EC.

Center for Infectious Disease Dynamics, Department of Biology, The Pennsylvania State University, Mueller Laboratory, University Park, PA 16802. USA.
Influenza A viruses from wild aquatic birds, their natural reservoir species, are thought to have reached a form of stasis, characterized by low rates of evolutionary change. We tested this hypothesis by estimating rates of nucleotide substitution in a diverse array of avian influenza viruses (AIV) and allowing for rate variation among lineages. The rates observed were extremely high, at >10(-3) substitutions per site, per year, with little difference among wild and domestic host species or viral subtypes, and were similar to those seen in mammalian influenza A viruses. Influenza A virus therefore exhibits rapid evolutionary dynamics across its host range, consistent with a high background mutation rate and rapid replication. Using the same approach, we also estimated that the common ancestors of the hemagglutinin and neuraminidase sequences of AIV arose within the last 3000 years, with most intra-subtype diversity emerging within the last 100 years, and suggestive of a continual selective turnover.
PMID: 16945980 [PubMed - as supplied by publisher]
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[gsgs]

Re: Avian Influenza Virus Exhibits Rapid Evolutionary Dynamics.

but I'm seeing fewer reassortments since 2004.
The current visuses: Qinghai,Indonesia,Thailand and most of China
are most from the same genetic background without reassortion.
This wasn't the case before 2004.
Also, the worldwide spread Qinghai strain seems to
evolve more slowly

 

[Mingus]

Re: Avian Influenza Virus Exhibits Rapid Evolutionary Dynamics.

The study do not mention reassortment, only point mutation probably calculated with a single pure strain that goin into multiples passage in a controlled culture medium

 

[gsgs]

Re: Avian Influenza Virus Exhibits Rapid Evolutionary Dynamics.

I would just measure the average number of differences in two sequences. But then you would have to sort the sequences
beforehand because the reassortments would significantly
falsify the picture. I had 488 H5N1 viruses with >8000
nucleotides available and 334 of those were the "modern"
strain , most since 2004 and no signs of reassortment
can be seen within those, while the other 154 viruses,
most from 2002 and before, showed much reassortment.
So, we see a concentration towards one reassortment-class.
And also, clearly the viruses from China show the largest diversity,
2 viruses from China in average differ much more than
2 viruses from Indonesia or Thailand.
When you just concentrate on the Vietnam/Thailand virus
or on the Qinghai virus, then I think the evolution rate
(variety-change per time) is not much different from normal flu (H3N2).

 

[Mingus]

Re: Avian Influenza Virus Exhibits Rapid Evolutionary Dynamics.

Many things will affecte the calculated rate.

That's why experiment must be done in a lab-controlled environement.

A single pure strain in multiples passage will calculate the point-mutation rate. Two different strain co-infecting a plate could show us different data because of recombination possibility.
I do not think we can extract relevant quantitative data from field.
( but that said, this is just my personnal opinion. )

 

[Ganseerpel]

Re: Avian Influenza Virus Exhibits Rapid Evolutionary Dynamics.

Has anyone the full text version?