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The genetic stability of Ebola virus

ROOSSINCK,MARILYN roossinck at aardvark.ucs.uoknor.edu
Wed Aug 2 13:54:00 EST 1995


In article <3vghtr$7nq at pipe3.nyc.pipeline.com>, ijiwaru at nyc.pipeline.com (Lyle Najita) writes...
>In article <c601591-2907951459500001 at 128.206.12.143>, Don Haut writes: 
> 
>>In article <evans-2807951508000001 at ganymede.ahabs.wisc.edu>, 
>>evans at ahabs.wisc.edu (PSE) wrote: 
>> 
>> 
>>> Does it surprise anybody that an RNA virus that has been replicating in 
>>> the wild for almost 20 years has accumulated very few variations at the 
>>> nucleic acid level?  Sanchez et al do not comment about the resulting 
>>> proteins, so many or all of these mutations may have been silent.   
>>  
>>> Is this the kind of variation that would be expected from an RNA virus 
>>> over such a time period due to genetic drift (ie: neutral evolution")?  
> 
>>> Is there any data about genetic drift in filoviruses, or other RNA 
>>> viruses? 
>> 
>>Given the replication strategy of filoviruses which is fairly simple (see 
>>Feldman et al.) I am not surprised.  All of this data might imply that the
> 
>>filovirus RNA dependant RNA Pol. is a very accurate Pol.  I think these 
>>are really interesting questions and it will be fun to see what the answer
> 
>>is. 
>It could as well be that not many mutations are tolerated.  In general RNA
>pols tend to be more error prone because they lack the proof-reading
>capabilities present in many DNA pols.  I would prefer to see the data on
>filovirus RNA-dep. RNA pol error rate before passing judgement on its
>accuracy. 
> 
>>  
>>> Does the lack of genetic changes imply anything about Ebola's natural 
>>> reservior?    
>> 
>>Possibly.  As Sanchez suggested, there may be extreme selective pressure 
>>to maintain the Ebola Genome as it is. 
>> 
>>Don 
>> 
>>Don Haut  
>>Molecular Microbiology and Immunology 
>>University of Missouri-Columbia 
>>C601591 at showme.missouri.edu 
>>314-882-3171 
>> 
> 
>just MHO, 
>L

Just wanted to add my own 2 cents worth--it is not clear that there is such a
thing as "neutral" evolution in an RNA virus--nucleotide changes that do not
effect coding capacity may well effect other functions of the viral RNA.  With
very limited genetic information the selection pressure on sequence maintain-
ence could be enormous.  We just don't have enough data yet to know why some
RNA viruses seem to change rapidly and some very slowly.

Marilyn Roossinck
The S.R. Noble Foundation



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