Saga of avian influenza virus is evolution in action

[andym]

The threat of the influenza virus has had the interesting side-effect of making those who might favor serious consideration for intelligent design implicitly recognize the validity of the theory of evolution (for example, GW Bush).

That's because what's really being discussed is the probability that the avian influenza virus will evolve into a version that can infect human beings efficiently.

Is anyone even considering that an intelligent designer is making variations in the flu?

The theory of evolution boils down to two parts: (random) variation and natural selection. In this case, scientists recognize that there is an available niche for the avian flu virus: the human population. They also know that in theory it is possible for an avian virus to vary in a way where it can jump to the human population (the 1918 Spanish flu, which preferentially killed healthy young people). So they are worried.

What they can't predict is IF and WHEN it will become a human pathogenic virus. What they do know is that variation is dependent on the number of viral particles that get replicated-- with millions of birds infected that means that there is ample opportunity for the virus to mutate. They also know that the virus is capable of borrowing genetic material from other flu viruses when both infect the same cell at the same time (reassortment). What can't be predicted well at the moment is how many and what specific mutations will make the avian flu virus into a virulent human flu virus. Bottom line: lots of variation is already happening. Perhaps some viral particles are already capable of causing a pandemic. But they need to find their niche (humans).

The key is that for natural selection to work, the virus needs to attempt to replicate in the new host-- in this case humans. So
the number of times the virus is able to get into human cells is the key to whether a variant can be selected that can efficiently infect human cells and become a human flu virus. That's why public health officials continue to kill infected birds, and isolate human cases.
If successful, avian influenza may never have the chance to become a human influenza virus.


So as scientists monitor the changes in avian influenza they are reviewing direct proof for the theory of evolution.

[joemurphy]

1. Nay! T'is but another sign of God's infinite complexity at work! n/t

[Peter Frank]

2. Or "Pestilence" -- one of the four horsemen of the Apocalypse nt

[Peter Frank]

3. But your point is well taken...

No matter how you slice it, this is empirical proof of evolution in real-time.

[StClone]

4. Can't be Evolution Viruses are not living organisms

Further, the mutations that occur are not forming a new "species" they are merely strains or variations of the original virus. I can see the use of this simple analogy as a satisfying way to push Darwin but it's inaccurate. Darwin's Theory of Evolution can stand on its own without resorting to Avian Flu mutability.

[andym]

5. Modern Evolutionary theory goes beyond Darwin

This is not quite accurate:
>"Can't be Evolution Viruses are not living organisms"
>Further, the mutations that occur are not forming a new "species" they >are merely strains or variations of the original virus.

Viruses straddle a middle ground between living organisms and inert chemical structures. The can not replicate by themselves, so they are not classical organisms, but in the presence of their host, they can replicate, so they are more than just inert chemical structures. Speciation classically (in the Darwinian sense) involves sexual reproduction-- if one organism changes in such a way that it can no longer (in theory) produce fertile offspring with other members of it's former species, but CAN reproduce with others carrying the same changes, then it represents a new species. It's true that this kind of speciation is not exactly relevant to viruses because they don't have sex (but see below), but that does not mean that viral change and alteration of phenotype is not representative of evolution-- quite the contrary.

Basically, whether or not classical speciation occurs, evolution is still at work, at least as understood in the modern sense by biologists.

> I can see the use of this simple analogy as a satisfying way to push >Darwin but it's inaccurate. Darwin's theory of Evolution can stand on >its own without resorting to the Avian Flu mutability.

It's not that the theory of evolution can't stand on its own, its that in the changes that occur in avian influenza we see the basic principles of evolution at work: natural selection and random variation.

In it's modern form evolution is not used just to explain speciation, but to explain biological change in the context of the environment. For example, see "Ecological and immunological determinants of influenza evolution." Nature. 2003 Mar 27;422(6930):428-33 This is an example of the modern understanding of evolution, published in a premier research journal. That's why evolution is considered so central to biological research, and why denial of evolution has potential serious consequences. You see biologists recognize that viruses are evolving!


Now, as an interesting aside, we can actually make a speciation argument for viruses (though it might be somewhat controversial, because of the organism argument you made). Sex can be generalized to recombination of genetic material (DNA or RNA). Influenza can "mate" with other influenza viruses by reassortment. If an influenza virus can no longer interact with another influenza virus by virtue of having a different host specificity then basically it can not "mate" with the other virus, and can be said to be a different "species."

[StClone]

6. Darwin Classic Interpretation

True, Darwin's Theories can be applied to anything where survival is equated with superiority of a definable organism, or to even to a group of competing ideas (Darwin, I.D. or Creationism for instances) in a given environment. And in a limited sense, there may even be reverse-Darwinism like selecting your favorite pair of jeans and wearing them out sooner.

I was interested in the Classical Interpretation of Darwinism as attacked by Fundies which advocates natural selection over God's eye for design.

[andym]

7. Viral evolution can be used against fundies

The critical point is not that Darwin's theories can be used anywhere survival is equated with superior things. The modern theory of evolution as applied to viruses, which are biological entities subject to mechanisms similar to that faced by all biological organisms, demonstrates two critically important things:

1) Mechanisms for genetic change that are similar to that which occurs in "organisms". (Darwin knew nothing about how such changes occurred-- that is part of the modern theory). In fact they depend to varying degrees on biology provided by their hosts, such as the ability to make proteins.

2) (Natural) Selection of the fittest.

These two principles apply to "organisms" and viruses and to various other genetic elements like transposons. The idea here is that here there is dramatic evidence of biological evolutionary processes occurring in real-time that validates the two driving principles behind evolution.

If a fundamentalist accepts these principles (of random variation and natural selection-- which of course have many other exemplars), then he or she is left with the argument that these somehow weren't working the past or aren't powerful enough to explain complex change, while admitting that they work well now for small to medium complex changes (like viral evolution). This last argument leaves them in a very precarious intellectual position with their supporters, because implicitly it forces them to admit that evolutionary processes exist, which many refuse to believe at all.

The reason for the problem is that significant change is occuring and an intelligent designer is not in control. So an intelligent designer is only needed for big changes. I think that is the beginning of the end for them.