In <Pine.3.89.9403020805.B7211-0100000 at kornberg.bio.uci.edu>,
Ananias Escalante writes:
:There is a paper by Tibayrenc et al 1991 that is relevant in
:this discussion:
:Tibayrenc M., Kjellberg F., and F. J. Ayala (1991) The clonal
:Theory of parasitic protozoa: a taxonomic proposal applicable
:to other clonal organisms. BioScience 41(11):767-774
:They conclude that genetic markers should not be used to separate
:species at least they correspond with "biologically significant
:differences", of course there is ambiguity in this assumption but
:it can be defined in each case. They suggested the use of a new
:term "clonet" to name the clonal lineages and a method of clone
:designation. They didn't discuss in deep the relationship of this
:term 'clonet' with ramets or genets previously used in the
:microbiology literature.
My questions have more to do with how to designate what Michel
Tibayrenc calls 'agamospecies'. He says that the major problems
with agamospecies are 1. that they have no rigorous definition
and 2. that their boundaries are arbitrary. I'm not sure that
this is always the case.
My original questions dealt with how one copes with the huge
genetic differences within agamospecies and how one handles
cases where agamospecies are polyphyletc based on genetic data.
I agree that the problem is probably intractable at this point
in time but some minimum standards for species description where
the only or primary source of diagnostic criteria is molecular
would be helpful. Otherwise the literature will become cluttered
with species descriptions based on molecular differences without
any information on the degree intraspecific variation.
Perhaps Michel could comment on the problem?
Graham
________________________________________________________
C. Graham Clark,
Laboratory of Parasitic Diseases,
National Institutes of Health,
Bethesda, MD 20892
Ph.: 301-496-4740
FAX: 301-402-4941
e-mail: cge at cu.nih.gov
