Taxacom: Barcodes and species

[Jared Bernard]

Rich, do you think the Chromis species who share barcodes would be "immune"
to population genetics studies? My own hesitations about barcodes (which
are the same hesitations about morphological holotypes) notwithstanding, I
would've thought that at least the barcodes within an interbreeding
population would be closer related to each other than with those in another
population, even within the same species. So, your case of two species
having identical barcodes makes me think you wouldn't even be able to see
any population structure within each species, let alone species
delineations. If you can't see any genetic distinction between species, how
could you tell if sisters are closer related to each other than cousins,
who are more related than a neighboring family?

But it seems most phylogenetic and even popgen studies have moved away from
single barcodes toward using thousands of genes or SNPs -- I think usually
both nuclear and mtDNA to avoid the polar bear fiasco ;^)
(doi: 10.1093/molbev/msy018). Do you think a method like that would help
analyze populations of Chromis? I guess my ultimate question is whether
genetic distinction could ultimately be found between the Chromis species;
if there is a way to say which populations are closer related than others,
then there ought to be some genetic cohesion within a species and a way to
distinguish it from another species. But maybe barcodes don't do the trick
in this case, even though they're supposed to be informative.
Jared