In February 2005,(BTS lectures Bristol) Stuart Longhorn gave a presentation on his ongoing work into the DNA of Brachypelma . Though his work is not yet finished he gave a fascinating look into the world of science and its application in determining species using DNA.
His work so far suggests that the Brachypelma genus will see some changes in the future, possibly being split into other genera.
The DNA evidence suggests that mesomelas (thought to be Brachypelma) is genetically divergent from all other species (so is not Brachypelma). It also suggests that annitha (argued to be a colour form of smithi), is a valid species
It is not known as yet when his work will be complete and published, but I suspect it will have far reaching implications, not only for Brachypelma but in other genera which would benefit greatly from a solid means of identification.
I believe Stuarts work is very important and will fill in some important gaps in our knowledge of Brachypelma, and look forward to the final publication.
It is suggested that this method could be used to establish better means of identifying CITES protected species, ( as the results were successful for spiderlings without colour or marking, and male and female adults alike), if a collection with verified specimens and their corresponding DNA results, were to be set up.
This method is known as DNA barcoding .
DNA barcoding is taxonomic method which uses a short genetic marker in an organism's
mitochondrial DNA to quickly and easily identify it as belonging to a particular species. It is based on a relatively simple concept: most eukaryote cells contain mitochondria and mitochondrial DNA (mtDNA) has a relatively fast mutation rate, which results in significant variance in mtDNA sequences between species and a comparatively small variance within species. A 648-bp region of the mitochondrial gene, known as cytochrome c oxidase I (COI), has been proposed as a potential 'barcode'.
So whilst it could be a useful tool in recognizing known species, (those tested and included in the data base), if a specimen is tested and does not match with any in the data base, how could it be determined if this was a protected species? As this method tests only a small piece of DNA perhaps it is limited in its applications.
For it to be successful the specimens tested and included in the data base would need to be from the type location of the original specimens and the morphology checked, by established taxonomic methods, against the existing type specimens, Because the originally described species ‘types’ are preserved , the DNA deteriorates, so fresh specimens would provide more reliable information. You would then need to establish the natural variants within the species group, (how does the DNA vary within the known species across its natural range in the wild). This would need to be done for ALL known species which are CITES protected, and also for the ‘look alike’ species.
It may be of use to check relationships between male and female specimens, where the collection location history is uncertain, if the preserved types are compared using this method. So it could have good uses for known species in certain applications, and could be useful to compliment the work of the traditional methods of taxonomy.