In arguing for the evolution of human males and chimp males from a common ancestor, but without female participation, one could point to common characteristics in human males and chimp males that are lacking in, let us say, giraffe males. One could thus perhaps create a fairly plausible discussion of primate-male species evolution in which females have no part. And DNA correspondence might be pointed to to bolster that argument.
That, I say again, is similar to what Dr. Hahn and her co-authors have done with SIV and HIV.
Good old American-style levity aside, I'm not in agreement with that at all. It doesn't make sense.
While they do discuss �host-dependent evolution,� they seem to think that there�s also a "host-independent" evolution. That second evolution is what�s shown in their evolutionary tree although there are subscripts (e.g., "agm" and "chimp") to remind the reader of the higher species with which the virus is associated.
No mechanism is suggested by which the human species could have rid itself of SIV while evolving. Indeed, the idea that the human race did somehow rid itself of SIV while evolving is an implicit assumption and no facts are given to support it.
When a person contracts HIV, the virus usually lives for many years as a provirus in the patient's cells. That the virus is able to integrate itself in that manner shows a very intimate pre-existing relationship between HIV and those human cells that are infected by the viruses. There's no reason to assume that the human cellular components that are involved in accomodating HIV weren't inherited by evolution from chimps. And there's no good reason to assume that HIV itself did not evolve from SIV by a slow evolutionary process with the female moiety involved in each generation of viral reproduction.
And, of course, If viruses do reproduce by means of a female moiety, as we are saying here, then the term viral "host" is misleading and shouldn't be used.
Bird flu viruses can jump from birds to humans. But the human flu virus also jumps from human to human. Human flu virus and the associated human female moiety for flu have evolved together. But It seems that, in evolution, the vertebrate female moiety associated with flu hasn't changed much, even over very long periods. Thus a cross-species jump is still possible. Such a thing could also be imagined, with SIV, between chimps and humans. But our authors seem to have made an assummption which isn't stated directly.
CONTINUE ARTICLE
