DNA Barcoding for Plant Taxonomy

dna barcoding

A typical 1ha of tropical rainforest may contain about 700 different plant species. Now, if you want to identify them, unless you are Alwyn Gentry that is a big problem.  A taxonomist is a weird creature with almost magical knowledge into the names of plants, and has highly specialized skills and vocabulary.

For a diverse set of conservation and ecological problems, the starting  foundation is always to  identify species correctly. Nothing is more boring than papers referring to species as  ” Bignoniaceae sp.1 , Bignoniaceae sp.2 etc”. Believe me, i have read a lot of them and you stay with the feeling you got nothing of value.So.. what is the solution? DNA barcoding.

DNA barcoding is  like giving every species a unique genomic signature. Basically what you do is take a short, standardized  and universal portion of the  genome, which can satisfy the criteria of having high variation among species but low variation in individuals. Then by sequencing, every species will have a unique ADN identifier.  For animals the choice is a portion of a mitochondrial gene for the cytochrome c oxidase (COI). Plants don’t have a unique barcode yet but a combination of two genes have been suggested, and the rbcL/ trnH-psbA combo has the best results for tropical plants.

Just imagine, being able to identify and name every plant species at your side,  and animals also. Currently samples must be taken to laboratories for correct identification , but portable barcoding devices will be ready in the near future. You will feel like Ash with his pokedex toy.

One of the biggest advantages of barcodes is that you can correctly identify plant species with fractions of the complete individual, name them wood, leaf or flowers, or seeds. In order to give every plant  its unique identifier, the best practice is to sequence type specimens from recognized herbariums.

A big challenge now is to integrate DNA and traditional taxonomy to generate a robust approach for the description and delimitation of species.  This is the reason DNA barcoding won’t replace the charismatic taxonomist, there is more need of them than ever. We need them to correct for errors in the sequencing, for describing new species, and to keep feeding the barcode databases like The Barcode of Life Data Systems (BOLD).

Please keep an eye on the advancements on DNA barcoding. Like John Kress says, it can be a windfall gain for tropical biology.


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