Presentation on theme: "The noisome weeds which without profit suck The soil's fertility from wholesome flowers. - William Shakespeare, The Tragedy of King Richard II."— Presentation transcript:
The noisome weeds which without profit suck The soil's fertility from wholesome flowers. - William Shakespeare, The Tragedy of King Richard II
It is not once nor twice but times without number that the same ideas make their appearance in the world. - Aristotle, "Manual of Greek Mathematics" by T.L. Heath (On The Heavens)
New.. but not good. - unjustified emphasis/reliance on DNA data - the incorrect analogy to Universal Product Codes (UPC) :typological thinking is not really new. - the concerted effort, but largely to do the wrong thing
Three related topics: 1. Voucher DNA/ database select sequences 2. DNA Taxonomy 3. DNA Barcoding Identification
Voucher DNA/sequences -a tool for museums & researchers to locate appropriate study material -this is not science,but is a good use of the data if funding is available
DNA Taxonomy -exclusive use of DNA sequence data to describe and define taxa -this is a scientific enterprise, just a deeply wrong one -clearly tied to DNA Barcode identification, promoted by many of the same proponents
Hence, also, it has been found, that a classification founded on any single character, however important that may be, has always failed; for no part of the organisation is universally constant. The importance of an aggregate of characters, even when none are important, alone explains, I think, that saying of Linnaeus, that the characters do not give the genus, but the genus gives the characters; for this saying seems founded on an appreciation of many trifling points of resemblance, too slight to be defined. -C. Darwin, Origin...
"Hebert envisages this "gene species" as a first, mandatory step towards describing a real species. At a later stage, traditional taxonomists could make the formal morphological description of the specimen, which would then become associated with its DNA barcode, he suggests." (BioMedNet 2003)
DNA Barcode identification -it's not research (J. Rodman NSF, Science, June 2003) -identification is not scientific; taxonomy is -identification tools are one product of systematics/taxonomy; they are not the purpose of the discipline
"...better keys, more keys, more images on the web, more web sites, more species pages, more descriptions, more phylogenies, more specimens, more maps, more anythings. Those are necessary collaterals, but not sufficient." (Janzen 2004)
"If taxonomists fail to embrace molecular technology, Hebert is clear about the consequences: "There is no more likely death of a discipline than the failure to innovate." (BioMedNet 2003) ---- Taxonomy is not a subject most people lay up at night thinking about, Hebert says. "There's also probably no discipline that has been so little impacted by technology." (Baltimore Sun 2003) DNA Barcode identification: mischaracterizes systematics and taxonomy
DNA Barcode identification: methodological confusion and problems -Phylogeny or profile? -Input order alters results -Euclidean distances?
Mitochondrial heteroplasmy Identical sequences in different species Introgression Hybrid speciation Incomplete lineage sorting NUMTs- Nuclear Pseudogenes DNA Barcode identification: methodological confusion and problems -mtDNA is it really any good?
DNA Barcode identification: methodological confusion and problems What about all the successful results? <1000 spp so far Highly selective, low sample numbers Systems where allopatry is most likely the cause of speciation Where are all the recently divergent species?
DNA Barcode identification: -ends and means- Hebert predicts $1 billion over 20 years (Science, June 2003) $2.5 billion and 20 years (Hebert- New Scientist 2003) What is really the cost? -Our ability to do the job right and the option value for the future.
As a tool after the completion of the taxonomy of a group Is our taxonomy complete enough? Who will do the taxonomy? Who will correct errors in the system? DNA Barcode identification: Is there any use at all?
Has not been promoted in a scholarly manner Questionable and confused methodology –Critical tests remain to be done –Highly selective test cases Mischaracterization of systematics and taxonomy Overstated utility of mtDNA DNA data for identification may be used only after the completion of the taxonomy of a group Summary-
Doing DNA Barcode identification is not doing science Distracts from the real objectives of systematics Reliance on DNA Barcode identification will lead to DNA taxonomy Results in a deficient product DNA Barcoding-The anti-PEET Summary-