DNA barcodes catalogue animals

[Doug Yanega]

>"It's an exciting tool - thus far I've been impressed by the 
>results," says museum entomologist Scott Miller. Members of museum 
>staff are discussing whether to launch a large-scale barcoding 
>effort for the museum's collections. Barcoding can work with small 
>fragments, such as an insect's leg, and on specimens collected 
>decades ago.

But note that he also said
-----
But it won't replace the traditional methods of identifying and 
classifying species by their appearance, he says: "It's one more tool 
in the box, but we will always need backup."
------
Hebert's claim that this appraoch would enable us to catalogue all 
life on earth in 20 years for $2 billion is the biggest crock of pure 
bull I've ever heard, and a horrendous slap in the face to the 
generations of taxonomists who've been laboring for over 200 years to 
get a handle on extant biodiversity. Just consider the implication: 
he's saying that in a 20-year interval, people could collect fresh 
material (or find fresh enough material in museums that is still 
sequenceable - when they say "decades" it means no more than 30 years 
old, and even then only if killed and preserved in a certain way) of 
every species from every habitat during every season in every country 
in the world. Yeah, right. All those hundreds of thousands of taxa 
known only from single specimens, or only from material too old or 
too improperly preserved to retain adequate DNA, could be re-captured 
with a trivial amount of collecting effort - and, on top of that, 
every species that has NEVER been collected before would also 
magically be caught and sequenced in the process. Is there a single 
person here who believes this?

And just look at the dollar amount: if a *whopping* 20% of the 2 
billion budget was earmarked for labor (as opposed to sequencing, 
databasing, cataloguing, collecting trips, and every other expense), 
at an average of, say $30 per hour (enough to pay a $60K annual 
salary), that would only give about 6K person/years of labor, meaning 
the equivalent of about 300 full-time researchers over that 20-year 
interval. He's expecting the task of collecting and sequencing 100 
million species to be performed with a total investment of labor 
equivalent to about 300 researchers' worth? Even if it was done by 
full-time researchers, each researcher is supposed to collect and 
sequence 333,000 species, with no duplication of effort? That's 
16,000 species a year, per researcher, or 333 unique species each 
week (and don't forget that someone has to sort them out and identify 
them *before* sequencing). He can't possibly have the slightest idea 
what he's talking about.

Moreover, genetic barcoding is completely divorced from any 
biologically meaningful concept of species; it is pure phenetics, and 
can yield identical results for different species, and - even more 
commonly - different results within a species, just depending on 
whether the chunk of DNA sequenced happens to have variability or 
not. It is not a panacea, not some miracle that will give us a 
complete tree of life - it's simply another set of data, and cannot 
be used to unambiguously declare the taxonomic status of any 
organism, let alone build a phylogenetic classification. We've long 
been aware of the increasing trend to marginalize morphological 
taxonomists, and now this trend has found a new and outspoken 
champion, Paul Hebert, to announce to the world that we've all been 
wasting our time, that only DNA holds the key, and that relying on 
DNA is cheap and easy. Excuse me if I publicly berate this as idiocy.

FWIW, portions of the above tirade are based on *other* articles 
detailing Hebert's explicit comments on how traditional taxonomy has 
utterly failed us, which the article cited by Olle did not get into.

Argh,
-- 

Doug Yanega        Dept. of Entomology         Entomology Research Museum
Univ. of California - Riverside, Riverside, CA 92521
phone: (909) 787-4315 (standard disclaimer: opinions are mine, not UCR's)
              http://cache.ucr.edu/~heraty/yanega.html
   "There are some enterprises in which a careful disorderliness
         is the true method" - Herman Melville, Moby Dick, Chap. 82
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