retroviruses; mammals

[Curtis Clark]

At 12:39 PM 9/28/99 -0700, Ken Kinman wrote:
>    Please tell me you were kidding and making a joke.  I completely agree
>with Tom's statement, even if the possibility of it happening are
>infinitely
>small.
>    However, viruses popping in and out of genomes is a totally different
>thing, so I do hope you were joking.

I might have been, but not intentionally. Viruses have histories, too, and
although I have little expertise in virology (read: none), I have read that
some retroviruses have domains, or produce products, or maybe both, that
are strongly reminiscent of normal mammalian genetics. The implication is
that they started out as pieces of mammals. So, phylogenetically speaking,
they *are* mammals (if, of course, that is how they originated).

Another more clear-cut example gets back to humans: Henrietta Lack, or more
specifically her ovarian cancer, cultured as HeLa cells, which have spread
by weedy clonal reproduction throughout many other cell culture lines.
Speciation, pure and simple (and no Mars required, just a shift in
reproduction from sexual to clonal).

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