Nature (451 pp617, 7 Feb 2008) has a review of the bar code approach to taxonomy as it applies to orchids. It notes that whilst huge progress has been made, the art is not yet definitive. This will be a relief for a few readers of this list, who are actively involved in this research.
Animal bar coding has gone rather quickly, settling on a gene called CO1. Plants have been harder, as various genes which have been used for one group of plants fail in another. The most recent contenders have been called matK, trnH-psbA (what is it with geneticists and names?) and atpF-H. Vincent Savolainen at RBG Kew has now reported in PNAS ( doi:10.1073/pnas.0709936105 ) that the first two of these, alone or in combination, could identify a test run of 86 species with a 90% accuracy. They then went on to look at 1036 species of orchid using matK alone. There are technical difficulties with matK in some species - it does not amplify easily, for example. It remains to be seen whether it performs as well when applied to something other than orchids. There is a shoot-out between the contenders being coordinated out of RBG Edinburgh by Peter Hollingsworth.THis looks at 675 unrelated species of plant, and will report in April. The point of all of this is, however, that plant bar coding is nearly with us, and that species orchid barcoding has, essentially, arrived. Whether this puts taxonomists out of business, or merely shifts the ground somewhat remains to be seen. However, what is essentially an art form (don't shoot! I'm on your side!) is likely to approach an end game in which we finally know what is truly different, what is related to what, and to which degree. ______________________________ Oliver Sparrow +44 (0)1628 823187 www.chforum.org _______________________________________________ the OrchidGuide Digest (OGD) [email protected] http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
