Identifying and cataloging biological diversity is challenging. One way to do go about IDing all the life forms is to sequence a known region of the genome in all those species. This is known as DNA barcoding. An article in PNAS reports on the DNA sequence of a gene found useful for DNA barcoding in plants. In a review of the paper, the following table is presented:
|Number of species||All (or most)||One (or few)|
|Number of gene regions||One (or few)||All (or most)|
The gist: DNA barcoding results in the sequencing of a single gene in a bunch of species, while genome sequencing gives us the sequence of an entire genome in a single species. This may be true now, but for how long? The dropping price of sequencing will allow us to get information from many genomic regions in many species. These won’t be high quality whole genome sequences, but the age of doing DNA barcoding with a single gene won’t last for long.