DNA Barcodes: measuring biodiversity on Earth

On Friday, I attended an interesting seminar on DNA barcoding by Dr. Paul Hebert, Director of the Biodiversity Institute of Ontario, Canada.

I had a basic idea about how you might go about “barcoding” life on earth, but I didn’t really understand why you would want to.  Paul’s talk illuminated me by explaining that having barcodes you can much more easily measure the biodiversity (i.e. the number of species) in any given sample, even if the individual species are not actually known/named.  To do this pre-barcoding would be impossible (not to mention prohibitively expensive), but when you have a barcode you can group species that have similiar barcode regions together in phylogenetic tree diagrams; this way you have an “at-a-glance” view of the species spread in the sample. Barcode regions are also being used to understand gene evolution, in a general sense.

Paul’s vision is that biodiversity be measured, like temperature – everywhere across the globe.  He asserted that we know (and spend) much more in space research than in exploring/ measuring our own Earth’s biodiversity!

DNA barcodes and biodiversity
DNA barcodes and biodiversity



Paul’s talk summary:


“The DNA Barcode community has spent the past decade developing systems for species identification based on sequence diversity in short, standardised genomic regions. Barcode targets have now been designated for all groups of eukaroytes, and their efficacy has been well validated. These DNA-based identification systems are transforming biodiversity science, but they are also creating large registries of homologous gene sequences. For example, sequence information for a 650bp segment of the cytochrome c oxidase 1 (COI) gene is now available for nearly 300,000 species of animals. Although this COI segment represents just 5% of the mitochrondrial genome, it is an effective sentinel for the evolutionary attributes of this genome. There are also hints that COI sequence diversity can provide insights into the evolutionary trajectories plastid and nuclear genomes and their host organisms. Although species identification and discovery are the core products of DNA barcoding, this work has implications for those interested in deep genomics across the diversity of life.”




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