Wellington College teacher Andrea Shaw spent 2006 at NIWA as a New Zealand Science, Mathematics and Technology Teacher Fellow. Her project work included sequencing shark DNA to determine DNA barcodes.
Andrea’s work was part of the ambitious Fish Barcode of Life Initiative (FISH-BOL), an international effort to collectbarcodes for all fish . This will mean that any fish, or part of a fish (such as a fish fillet), can be identified by DNA analysis.
The FISH-BOL project
The Fish Barcode of Life Initiative (FISH-BOL) is one of the Consortium for the Barcode of Life’s (CBOL) major barcoding projects. In May 2009, more than 6,500 fish species had been barcoded out of an estimated 29,112. You can visit the homepage of FISH-BOL to find out the latest number of barcoded fish species.
For scientists to compare species across the world, they must all use the same. Therefore, all DNA barcoding projects compare the same region of the mitochondrial cytochrome c oxidase subunit 1 (CO1) gene.
For further information, see article: The ideal barcoding gene.
Samples of shark DNA
Andrea was comparing shark DNA barcodes. The shark DNA samples come from several sources. A sample can be taken from live sharks using a small, harmless fin clip, or samples can be taken from sharks captured off the New Zealand coast.
Extracting and sequencing shark DNA
A small sample of flesh is taken from the shark and then DNA is extracted from it. DNA for the CO1 gene isfrom the sample using (PCR) and checked on a gel. The sample is then sent overseas where it is sequenced. The DNA sequence acts as a unique barcode that can be compared with other species of shark.
Why do we need fish DNA barcodes?
There are a number of benefits for establishing DNA barcodes for all fish species, including:
- to conserve fish numbers by helping track fish populations and set fishing quotas
- to prove identity and prevent consumer fraud, where high-value fish products are substituted with ones of less value.
See these videos taken by students on Sequencing shark DNA.