rankless nomenclature

[Philip Cantino]

Andrew Rindsberg asked:

>
>How are hybrids accommodated in phylogenetic nomenclature? How does
>phylo-nomenclature deal with other organisms whose genetic material has been
>derived from more than one source?
>


The rules for naming hybrids under the PhyloCode (Art. 16) are
similar to those under other codes.  A taxon of hybrid origin may be
indicated by placing the multiplication sign in front of the name.
An organism that is a hybrid between named taxa may be indicated
through use of a hybrid formula--that is, by placing the
multiplication sign between the names of the parent taxa.

If it is not clear whether a set of hybrid organisms represents a
taxon (as opposed to a set of independently produced hybrid
individuals that do not form a species or clade), the PhyloCode
recommends that authors use a hybrid formula rather than giving the
organisms a name.

Where things get more interesting is determining the broader
nomenclature of taxa that have a hybrid origin, since a hybrid may
be a member of non-nested clades.  This is not addressed in the draft
PhyloCode but has been the subject of recent active discussion on the
PhyloCode listserv.  (Incidentally, if anyone would like to join this
listserv, instructions for doing so can be found at the PhyloCode web
site--http://www.ohiou.edu/phylocode/.)

The PhyloCode does not currently address your second question, which I
assume refers to phenomena like lateral gene transfer, but this
too has been under discussion.

It will be a few years before the PhyloCode is implemented, and this
is one of the things that remains to be ironed out.

Phil



Philip D. Cantino
Professor and Chair
Department of Environmental and Plant Biology
Ohio University
Athens, OH 45701-2979
U.S.A.

Phone: (740) 593-1128; 593-1126
Fax: (740) 593-1130
e-mail: cantino at ohio.edu