Scientists have long harboured dreams of identifying and cataloguing every species in existence, anywhere on the planet.

In some cases, it’s easy to tell species apart – a cat versus a dog, or a turtle versus a tulip.

It’s not always that simple. Often, species appear identical to the naked eye. Often, the only way to tell them apart is through DNA.

That’s where DNA barcoding comes in.

In a little over a decade, it’s gone from an idea in the mind of a University of Guelph professor to one of the largest biodiversity research sectors in the world.

About 500,000 new species have been identified by their DNA in that time – bringing the worldwide total to 1.7 million.

Scientists estimate that the real number of species in existence could be 10 million, or even higher.

“We’re discovering a lot of new species even (in) Canada, and this is not a rainforest or anything of that sort,” Dirk Steinke, the director of education at Guelph’s Biodiversity Institute of Ontario, said in an interview.

Paul Jannetta toured the institute while he was searching for an internship.

He liked what he saw, and has ended up spending five years there.

“It’s definitely important to know what you’re consuming,” he said.

Uses of DNA barcoding aren’t limited to the esoteric.

In 2009, Steinke’s team worked with CTV Montreal to analyze 48 samples of sushi from 16 different restaurants in the city.

Working with the DNA of the sushi, they found that 20 of the samples weren’t the fish claimed on the menu.

The discrepancy was most pronounced with red snapper, which was supposed to be in 12 of the pieces of sushi.

“Not a single one of the samples they brought back was actually red snapper,” Steinke said.

“It was tilapia, which is a very cheap farmed fish.”

More recently, the researchers have been testing herbal supplements to determine whether the ingredient listed as the “active ingredient” is actually providing the promised health benefit.

Often enough, Steinke said, the products are found to be full of filler material – and in some cases, the plants used might actually be harmful to human health.