One origin? (viral evolution)

Thomas Lammers lammers at VAXA.CIS.UWOSH.EDU
Fri Jul 20 13:20:46 CDT 2001

At 09:54 AM 7/20/01 -0700, Curtis Clark wrote:

>Snakes are tetrapods, even though they have no legs, because they are
>members of the tetrapod clade, descended from the first tetrapods.
>Likewise, eukaryotes are a clade, and eubacteria may be a clade (although
>I know that Ken disagrees), but "prokaryotes" are a grade.
>If a mammalian virus is a piece of mammalian DNA gone astray, it is a
>eukaryote, and in fact it is a mammal. Viruses being what they are, they
>have little trace of their ancestry, but I would venture that the
>differences in gene regulation and genome structure between eubacteria and
>eukaryotes might be reflected in viral genomes, and that we could thus
>understand their relationships.
>"Defining" prokaryotes and eukaryotes by their nuclei is essentialist.
>Let's instead ask what we can infer about lineage groups.

All well and good.  But I think that cladistic phylogeny carries with it an
unstated assumption that the evolutionary events it reflects are the result
of sexual reproduction of whole organisms, n'est ce pas?   I do
not  believe the methodology functions well when we are dealing with bits
of the organism that have taken on a life of their own.

Thomas G. Lammers, Ph.D.

Assistant Professor and Curator of the Herbarium (OSH)
Department of Biology and Microbiology
University of Wisconsin Oshkosh
Oshkosh, Wisconsin 54901-8640 USA

e-mail:       lammers at
phone:      920-424-1002
fax:           920-424-1101

Plant systematics; classification, nomenclature, evolution, and
biogeography of the Campanulaceae s. lat.

"Today's mighty oak is yesterday's nut that stood his ground."
                                                 -- Anonymous

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