Azara Blog: DNA "barcode" for plants is proposed

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Date published: 2009/07/29

The BBC says:

An international team of scientists has agreed on a standard "DNA barcode" for plants that will allow botanists to identify species quickly and easily.

They hope the agreement will lead to the formation of a global plant DNA library, which can be shared by the scientific community.

The barcodes are expected to have a number of uses, including identifying illegal trade in endangered species.

The findings appear in the Proceedings of the National Academy of Sciences.
...
The four-year project was carried out by the Consortium for the Barcode of Life (CBOL) Plant Working Group, which consists of 52 scientists from 10 nations.

Unfortunately the paper was not yet available on the PNAS website when the BBC published this article. Fortunately a Nature news story on the paper adds details that the glowing BBC article fails to mention:

...
A Who's Who of barcoding scientists can be found in the 52 authors of the new paper, which compares seven different DNA regions and assesses their suitability for a unique identifier for plants. The authors recommend that the barcode combine two regions, known as rbcL and matK.

Together these provide unique identification of 72% of the species tested and identify the correct species group for the rest.
...
[David Schindel, executive secretary of the CBOL] told Nature that providing the CBOL's plant working group can submit its recommendation within the next two weeks a decision should be made in the following six weeks. A final decision will come down to one of three possibilities, he says: the two-loci suggestion from the expert group, a three-loci code and a two-loci code plus an optional "insurance policy" region.

"I would say the first is the most likely, but I don't want to short-circuit the process," says Schindel. When a final decision comes, he says, "It's going to open up the flood gates."

Well 72% is pretty pathetic, although apparently this figure could improve over time. And given that low figure, the Schindel statement is rather worrying. So one of the points of this barcode better be that it is good enough for a very long time (decades), because if and when it gets changed all the barcoding is going to have to happen all over again. And it seems likely that a > 2-loci code makes more sense in the medium to long term, if not in the short term. So the CBOL is perhaps too anxious to make a decision which allows the "flood gates" to open, i.e. grants to be awarded based on the barcode having been defined. (And the biologists of the future will no doubt be happy to have to do the work all over again since that means more grant money then.)

The CBOL press release adds another caveat:

The selected plant barcode involves portions of two genes (rbcL and matK) from the plastid genome. Plastids are structures that are found in most plant cells and among other things, are involved in the process of photosynthesis.

So the relevant genome is not even in all plant cells. Still, it's a start.

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