Barcoding is a technique in which researchers sequence a small region of the genome of an organism and use this sequence information as a "tag" to identify species/types. The term barcoding is most commonly associated with sequencing a small portion of the mitochondrial genome of a multicellular eukaryote. There is a new paper in PLoS One discussing barcoding: Neotropical Bats: Estimating Species Diversity with DNA Barcodes. The paper seems potentially interesting. But I could not get past the part where they write "To the best of our knowledge, it is one of the largest molecular surveys of biodiversity."
Let's examine this statement a bit. In the study here the authors did a heroic task - they did barcoding for some 9000 individuals. It is impressive, in many ways. But one can only call it a large molecular survey of biodiversity if one thinks biodiversity = plants and animals. If however you include microbes, as of course you should, then this new study is not even remotely the "largest molecular survey of biodiversity." In fact, one could argue that 100s if not 1000s of studies of biodiversity of microbes are "larger" in many ways than this study. In microbial studies 9000 "individuals" are characterized routinely in most studies via the use of collecting DNA from environmental samples and sequencing genes from 100s -1000s to even billions of individual cells in a sample. This is done routinely in both metagenomic work (where one collects DNA from the environment and randomly sequences it) or ribosomal RNA PCR surveys where one collects DNA and then sequences rRNA genes from the sample. Overall, hundreds of microbial studies cover more biodiversity than this one - more species - wider phylogenetic diversity - more samples even.
Let's examine this statement a bit. In the study here the authors did a heroic task - they did barcoding for some 9000 individuals. It is impressive, in many ways. But one can only call it a large molecular survey of biodiversity if one thinks biodiversity = plants and animals. If however you include microbes, as of course you should, then this new study is not even remotely the "largest molecular survey of biodiversity." In fact, one could argue that 100s if not 1000s of studies of biodiversity of microbes are "larger" in many ways than this study. In microbial studies 9000 "individuals" are characterized routinely in most studies via the use of collecting DNA from environmental samples and sequencing genes from 100s -1000s to even billions of individual cells in a sample. This is done routinely in both metagenomic work (where one collects DNA from the environment and randomly sequences it) or ribosomal RNA PCR surveys where one collects DNA and then sequences rRNA genes from the sample. Overall, hundreds of microbial studies cover more biodiversity than this one - more species - wider phylogenetic diversity - more samples even.
