In article <3vrrkv$v86 at hydra.cc.umb.edu>, g1687jkarh at umbsky.cc.umb.edu wrote:
> In Article <anon-3107951716400001 at ganymede.ahabs.wisc.edu>
>anon at ahabs.wisc.edu (anon) writes:
>> >Why do we see so few _total_ (silent and non-silent) changes between in
> >Ebola 1995 and Ebola 1976...viruses separated in time and space.
>> I thought RNA viruses mutated alot. Host cell interactions shouldn't
> significantly select against silent mutations. How much similarity is seen
> between Ebola 1976 and Ebola 1995? I've heard that viruses tend to not change
> much if kept at -70 C, could this be the reason the 2 strains are so similar?
You won't find many places (outside expensive ultra-cold freezers) at -70
C on earth (especially in Zaire!). The reason that the viruses don't
change at -70 c is that they are not replicating, and are usually being
held in storage between experiments. I don't buy the conspiracy thing here
(no one would be stupid or callous enough to release ebola from storage).
It is interesting to note that when H1N1 influenza viruses re-emerged in
1977 (it was replaced in circulation by H2N2 strains in 1957) the viruses
were almost identical to the 1957 strains. This is odd as influenza is a
very variable virus. However, in avians (where it has reached adaption)
influenza virus strains show little variation in their vRNA sequences
despite continual propogation within the avian population (at least as far
as I can remember). But then ebola and influenza are two unrelated
viruses (despite the fact that both are negative strand RNA).