Punctuated Equilibrium and Virology

[crjmurray]

As most of you should know by now, I am not a scientist of any sort so please excuse my ignorance here.

I have a question about viruses and their ability to adapt.

If a virus is isolated to a certain geographical area and has a single method of infection in that area, what is the possibility of that virus gaining a new method of infection if it is introduced (and able to spread) to a new environment with different selection pressures?

Feel free to correct me if I've made some sort of fundamental misunderstanding here.

 

[crjmurray]

Bump

 

[essentialsaltes]

As most of you should know by now, I am not a scientist of any sort so please excuse my ignorance here.

I have a question about viruses and their ability to adapt.

If a virus is isolated to a certain geographical area and has a single method of infection in that area, what is the possibility of that virus gaining a new method of infection if it is introduced (and able to spread) to a new environment with different selection pressures?

Feel free to correct me if I've made some sort of fundamental misunderstanding here.

I'm ignorant of virology, too, but maybe you can expand on your question. When you say "new method of infection", what do you mean?

Do you mean a virus that formerly only infected species A, can now infect species B?
Or a virus that could only be spread by blood can now infect by sneeze?
Or do you mean that the biochemical method that lets the virus into a cell changes to a different method?
Any or all of these?

I don't know the answers, but maybe if you focus on one of these questions, someone who does know may comment.

 

[crjmurray]

I'm ignorant of virology, too, but maybe you can expand on your question. When you say "new method of infection", what do you mean?

Do you mean a virus that formerly only infected species A, can now infect species B?
Or a virus that could only be spread by blood can now infect by sneeze?
Or do you mean that the biochemical method that lets the virus into a cell changes to a different method?
Any or all of these?

I don't know the answers, but maybe if you focus on one of these questions, someone who does know may comment.

Any and all of those actually.

 

[essentialsaltes]

Viruses have certainly jumped species. Even across such unlikely divides as plants to insects.

 

[crjmurray]

Viruses have certainly jumped species. Even across such unlikely divides as plants to insects.

Interesting stuff. Thanks.

 

[crjmurray]

Seriously? No discussion on this?

 

[Subduction Zone]

Seriously? No discussion on this?

sfs seems to be very well educated in the field of biology. Perhaps a private message to him could get the ball rolling.

 

[crjmurray]

sfs seems to be very well educated in the field of biology. Perhaps a private message to him could get the ball rolling.

Tried that.

 

[Subduction Zone]

Tried that.

Well this subject is out of my wheelhouse so I can't help you.

 

[Loudmouth]

As most of you should know by now, I am not a scientist of any sort so please excuse my ignorance here.

I have a question about viruses and their ability to adapt.

If a virus is isolated to a certain geographical area and has a single method of infection in that area, what is the possibility of that virus gaining a new method of infection if it is introduced (and able to spread) to a new environment with different selection pressures?

Feel free to correct me if I've made some sort of fundamental misunderstanding here.

In puctuated equilibria, the strongest selection pressures are at the edges of a species range, so what you describe is certainly feasible. If a virus only infected species A, then it would have a tough time being transmitted at the edges of a species range since there is more distance between each possible host. The selection pressure would force the virus towards different strategies, such as being able to survive in the environment longer, a longer incubation time, a less severe and chronic infection, or even transmission to a new species. The small changes would build up in small populations at the edge of the range until the virus is much more virulent. At this point, it can sweep back towards the middle of the host range. The sudden appearance in the larger population would be a punctuated event.

"Only a small portion of the world has been geologically explored. Only organic beings of certain classes can be preserved in a fossil condition, at least in any great number. Widely ranging species vary most, and varieties are often at first local, -- both causes rendering the discovery of intermediate links less likely. Local varieties will not spread into other and distant regions until they are considerably modified and improved; and when they do spread, if discovered in a geological formation, they will appear as if suddenly created there, and will be simply classed as new species." [Charles Darwin, Origin of Species 1st Edition 1859, p.439]​

 

[crjmurray]

In puctuated equilibria, the strongest selection pressures are at the edges of a species range, so what you describe is certainly feasible. If a virus only infected species A, then it would have a tough time being transmitted at the edges of a species range since there is more distance between each possible host. The selection pressure would force the virus towards different strategies, such as being able to survive in the environment longer, a longer incubation time, a less severe and chronic infection, or even transmission to a new species. The small changes would build up in small populations at the edge of the range until the virus is much more virulent. At this point, it can sweep back towards the middle of the host range. The sudden appearance in the larger population would be a punctuated event.

"Only a small portion of the world has been geologically explored. Only organic beings of certain classes can be preserved in a fossil condition, at least in any great number. Widely ranging species vary most, and varieties are often at first local, -- both causes rendering the discovery of intermediate links less likely. Local varieties will not spread into other and distant regions until they are considerably modified and improved; and when they do spread, if discovered in a geological formation, they will appear as if suddenly created there, and will be simply classed as new species." [Charles Darwin, Origin of Species 1st Edition 1859, p.439]​

That's what I'd gathered from what little I read. Thanks for the response.