molecular types

James B. Whitfield jwhitfie at COMP.UARK.EDU
Sat Nov 9 15:47:52 CST 1996


Dear Taxacomers,
        It seems to me from the discussions of type specimens that one
limitation of most forms of molecular "vouchers" or types is that only a
limited amount of comparative information is easily available, at least at
any one time.
For practically any close species comparison, genes can very likely be
found for which there is essentially NO variation between the compared
species. Does this mean they are not different?  If so, maybe humans and
chimps are the same species!  Having data from one or only a few genes
gives you some information, but by itself tells one nothing about species
boundaries.
        Thus, either a complete genomic extract needs to be used as the type
(this can be done but it would be a LOT more effective for systematists if
a sample from a specimen is taken and the remainder of the specimen is
available for morphological comparisons).  Of course, with prokaryotes,
protists and viruses such subsampling is clearly impossible. For those
taxa, a choice clearly has to be made.  As a molecular systematist, I would
vote NOT to allow molecular samples as types (but insist instead on voucher
specimens being deposited from molecular studies) unless no other method is
available.  After all, you can recover DNA from specimens but not the
reverse (at least in the forseeable future).
        On the other hand, it would be nice if, in the case of clearly
conspecific type series, part of the series could be saved in a form
suitable for molecular sampling.
                                                        Cheers, Jim Whitfield

J. B. Whitfield
Department of Entomology
University of Arkansas
Fayetteville, AR 72701
(501)575-2482 FAX -2452
jwhitfie at comp.uark.edu




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