Now, Herbert oversees that repository, called Barcode of Life database, where the database of what different species’ CO1 genes look like is kept. Right now, there are 112,547 animal species in the database, and almost 43,000 plant, fungi and other types of organisms.
Researchers like Birck doesn’t often run into problems finding what he needs in the database, since the species he’s looking for are commercially valuable. But there are times where barcoding can’t provide an answer, as the barcode library is far from complete. It simply doesn’t have information about many creatures, like pythons from Southeastern Asia, for instance. So for barcoding to become really useful for someone like Kolokotronis examining the crocodile meat in Chinatown, many more samples need to be added to the database.
Herbert and his group have enlisted biologists all over the world to incorporate barcoding into their fieldwork to keep the database growing. The hope is that all collaborators will barcode five million specimens representing 500,000 species by 2015. The more samples they have in the database the more scientists can hope to use the technique to barcode everything from a whole environment to a cup of seawater.
Tricks of the trade
That said, barcoding can’t provide an answer when there is no DNA left to extract. While Birck can get DNA from most foods and some products, there are certain processes that destroy most traces of genetic material. “A Slim-Jim is fine,” he says, “you can get DNA out of that. Leather, probably not.” Things treated under high temperature and pressure can often come out without any DNA. This includes canned tuna. “I can get DNA out of mayonnaise,” he laughs, “but canned tuna is hard.”
There are sometimes workarounds for answering questions that barcoding can’t. Birck laughs as he describes one case in which they got a little snippet of fur that had come from a stuffed cat. The sellers were claiming the fur was fake, but someone at customs suspected it was real cat fur that had been glued onto the outside of the toy. Birck tried, but couldn’t get any DNA from the hair, or from the plastic like material the hair was glued to. Thankfully, their lab handles all sorts of materials, and he handed the fur to someone who specializes in textiles and fabrics. A quick look under the microscope confirmed that it was, in fact, real cat hair.
The US Customs and Border Protection is hoping to open similar testing facilities in other ports over the coming years. They also are trying to spread the word to enforcement officials across the country that the lab in Newark even exists. Many people, Birck says, have no idea that they can send their suspicious samples to the lab for testing. Which means a lot of material either passes through, or is held indefinitely when agents don’t know what it is. On the ground, they might get a box of fillets and have to make a decision based on gut instinct, while Birck can make a decision based on a precise test.
Other times, however, there’s not much you can do. And some plant species will never be barcoded to the species level. Sometimes investigators just can’t get DNA. And Kolokotronis still doesn’t know what species his Chinatown meat is from.