[Taxacom] barcode of life

[Kenneth Kinman]

 Dear All, 
        I agree that using COI alone, or any other gene
sequence alone, as the single marker for species delimitation, is a bad
idea. Until we have whole genome sequences for a very large number of
species, perhaps a combination of two or three independent genes (of
which COI is just one) would be a good compromise. What the other one or
two genes that would best evolve at different rates (than COI), I can't
say. 
              In any case, I find it
disturbing that COI gene sequences would too often be used to excuse
naming new full species, as opposed to subspecies or populations, based
on some arbitrary number of changes in that single gene. Barcoding for
identification of populations is probably valuable, but whether those
populations are subspecies or full species is a whole different matter
that a single gene cannot possibly determine across the whole gamut of
organismal evolutionary rates.  Bar Code of Life based on this single
gene has its place at this time, and may even be useful as a species
deliimitator in some taxa. However, extrapolating beyond those
limitations (without corroboration from other lines of evidence) can be
a risky proposition that will cast doubt upon the work of those who
delve too quickly into that kind of speculation based solely on a single
gene sequence.       
                      ----------Ken
Kinman                      
P.S. I am still convinced that the earlier (and still common)
fascination with the 16S ribosomal gene sequence (used for delimiting
much broader taxa) was equally suspectible to overextrapolation.  To
this day, such overextrapolation seems to continue to be a persistent
impediment to a true understanding of the higher level evolution of
prokaryotes, early eukaryotes, and even how various subgroups of
metazoans are related to one another.  Once scientists get addicted to a
particular gene sequence, it is an extremely difficult addiction (and
point of view) to argue against.  Once a single gene sequence (COI or
16S RNA) becomes a favorite of federal funding, there is an INCREASING
risk that a growing number of researchers will overextrpolate from and
overinvest funding on those particular genes.  Unfrotunately but not
surprising.              
       It's similar to the media's current fascination with the Gulf Oil
spill, but they will totally ignore other environmental threats until it
is also too late.  They almost always try to close the barn door well
after it is too late.  Reactivity continues to be the norm, and
proactivity is unfortunately relatively uncommon and unprofitable.  I
guess it is no surprise that big corporations are often tempted to cut
corners (penny wise, but pound foolish).  Oil companies are the present
targets of public and media scrutiny, but that only allows Wall Street
to slip back into their old habits.  Letting the latter take advantage
of the most recent events shows how the media can overreact to one
problem and then be totally distracted from covering another major
problem.  Not to excuse Wall Street greed, but perhaps it is at the root
of Oil companies cutting corners to keep their stock prices up.  Either
way, it is overpaid CEOs and their middle men that rake in the absurd
salaries and stock options, and the real lower-level workers in their
companies (a very few who become whistle-blowers to abuses) are far less
well paid and likely to become fired, demoted, or scapegoats for their
superiors.  Anyway, this is getting a little too far afield from
taxonomy, but I guess these problems tend to trickle down from
governmental funding at the top to those getting some benefit (large or
small) from those spending decisions.  Suffice it to say that
superificial PR too often prevails and superficial and repetitive media
is more likely to repeat that PR than to dig deeper for the less
exciting truth.  In the present scheme of things, anyone who still
believes that the meek shall inherit the Earth are in for a long wait
and further disappointment.  PR, money, and media access are still the
major power brokers, and the meek have little influence whatsoever, and
then only by rare accidents of very marginal media coverage.