>Well, what I thought was, that it is difficult to give DNA data character
>states that represent a whole species since mutations are always occuring
>(more so in some areas of the genome than others). In addition, I understood
>that most of this DNA data could be  representative of, perhaps, a population
>but is difficult to infer that it applies to the whole species. Maybe I'm
>wrong?
 
 
It depends on what you are looking at.  For the features that are likely to
be variable at the species level, it is important to sample different
populations to test how variable it is within and between species for the
group you are examining.  Certain spacer sequences are constant throughout
some species and vary between copies in an individual of a very different
species.  Other genes show little variation within a genus, and a single
individual provides adequate information.
 
David Campbell
 
"Old Seashells"
 
Department of Geosciences
CB 3315 Mitchell Hall
University of North Carolina at Chapel Hill
Chapel Hill NC 27599-3315
USA
 
919-962-0685
FAX 919-966-4519
 
"He had discovered an unknown bivalve, forming a new genus"-E. A. Poe, The
Gold Bug