Barcoding (animal) life

Andrew Mitchell mitchella at NU.AC.ZA
Tue Feb 4 02:09:00 CST 2003


“Barcoding” life is such a simple idea, I’m kicking myself for not thinking
of it first. Really it’s worse than that, I did think of it first-- as far
as I know :) --but I rejected the idea because I wasn’t thinking on a grand
enough scale and seeing all the possibilities. Similarly, I detect the
green-eyed monster lurking in the ether(net) of Taxacom. The most
vociferous responses are from those who feel threatened and think their
already-shrinking funding is going to be diverted to other sources. Have
you read the actual paper (Hebert et al. 2003. Biological identifications
through DNA barcodes. Proc. Royal Soc. Lond. B 270: 313-322) and not just
the inflammatory Op-Ed pieces, which go something like “Morphologists, what
percentage of life have you described in the 250 years since Linnaeus? Only
10%? Geez, time to move over!”

We’re not talking about diverting money from morphology into molecules but
rather of increasing the size of the whole pie, with molecules taking the
lion’s share it’s true (so what’s new?), but with undeniable spinoffs for
morphology-based systematics too (see below). Hebert et al. estimate that
it would take $1 billion to do the job they propose, although costs for
these large projects have a way of blossoming as they progress. What did
you think, that this money was going to be deducted from your budget for
2004?

If and when a noteworthy DNA sequence is discovered (e.g., a very divergent
sequence, or one that takes an interesting (e.g. basal) or otherwise
unexpected position in the gene tree) and confirmed, what’s gene jockey to
do?  Call you in of course because you’re the expert on that taxon, and you
can shed further light on the apparent anomaly. If you’re wise you get in
there at the beginning and steer some money towards your favourite taxon...
I’m sure you can make a good case for the sequencing starting there.

Nobody is proposing a species description that reads: !! !! !   ! !...
ACGGTAT... without at least a few good pictures of the beast (including
genitalia or other important features where appropriate, perhaps?) and
collection data, etc. (although that was indeed a witty comment someone
made—sorry I can’t find the pipe character on my PC keyboard to do it
justice). Clearly detailed morphological work by a trained expert is
preferable, but how long must we wait? There’s no need to rehash the
figures we’ve seen on this listserv on the numbers of undescribed taxa
versus the number of taxonomists—we all know it’s a dire situation. And
just how much time do we have to catalogue the earth’s biodiversity before
it is gone? But there’s no arguing the point that DNA sequencing is faster
than good morphological work. The “barcoding” solution can never and will
never be the final solution but it sure as hell will give us a usable
roadmap. The DNA sequences and resulting gene trees will form the backbone
for exploration of uncharted territory. And THAT is the point. As I see it
this is not a “molecules versus morphology” argument (if it is to you, then
get over it already... that debate fizzled out in the last decade!).
Barcoding will advance systematics, period.

------------------------------------------------------------------------
Andrew Mitchell
Senior Lecturer, Molecular Phylogenetics
School of Molecular and Cellular Biosciences
University of Natal
Private Bag X01
Scottsville, 3209
SOUTH AFRICA

Tel:  +27 (0)33 260 5815
Fax: +27 (0)33 260 5462

http://www.nu.ac.za/biogen/mitchell.htm




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