student questions

Louis Altamura altamurl at mail.med.upenn.edu
Mon Sep 22 01:33:11 EST 2003


Hi Grant ...

Here are my thoughts to your questions ...

> First why is the GP mostly used for mutation studies, is it because it causes
> cytotoxicity?

I am not sure which studies you are referring to, but if when you say
"mutation studies" you mean genetic variation in GP in reagrds to different
viral isolates, then I suppose there may be two reasons. (1) It could just
be that the people interested in Ebola may generally be just more interested
in GP vs. other Ebo genes. I work in a Micro department that is more focused
towards viral entry, so I may just be biased in this regard. (2) I am not
much of an evolution expert, but in general the greatest selection put upon
a viral component is towards those that are most visible to the immune
system. The surface glycoproteins will generally have the highest
variability merely because they must evade the host immune system.

> Second, which has more affect on EBOV, natural selection or genetic drift? And
> if natural selection has more affect, is it the mutations in the strain that
> have been selected on that allow its' survival or something else, like
> pleomorphisms?

I would say that natural selection probably has little to do with Ebola
variation. Actually, if you look at outbreaks of the same serotype that are
several years apart, the virus is generally highly similar. Also, Ebola has
probably evolved in a highly complementary manner to whatever it's natural
host is. Humans and monkeys are probably not the natural host; and that is
why we die from Ebola. However, because Ebola is so pathogenic to humans and
has such a rapid progession to lethality, this rellay doesn't allow for much
evolution to take place. The host is dead before the novel virus can be
passed on to another. HIV, on the other hand, remains in the host for many
years and can be spread as it evolves to combat a variety of antiretroviral
drugs.

I hope my thoughts here help. It has been some time since I took a solid
evolutionary biology class, so I may not be 100% correct. But anyway, good
luck.



On 9/9/03 5:18 AM, in article
Pine.LNX.4.43.0308141727370.15591 at hymn01.u.washington.edu, ""Douglas G.
Osborne"" <dosborne at u.washington.edu> wrote:

> 
> Hello my name is Grant Osborne, I am currently researching the EBOV for an
> undergraduate evolutionary project and wanted to ask you some questions as
> part
> of the project.
> First why is the GP mostly used for mutation studies, is it because it causes
> cytotoxicity?
> Second, which has more affect on EBOV, natural selection or genetic drift? And
> if natural selection has more affect, is it the mutations in the strain that
> have been selected on that allow its' survival or something else, like
> pleomorphisms?
> That is about all the questions I have for now. I would be very glad to hear
> back from you with answers. Hopefully my questions do not seem too vague.
> Thank
> you. 
> 
> 
> 
> 
> ---
> 

-- 
Louis Altamura
Ph.D. Candidate in Cell and Molecular Biology (Microbiology/Virology)

University of Pennsylvania
302B Johnson Pavilion
3610 Hamilton Walk
Philadelphia, PA 19104





More information about the Virology mailing list