For nearly 260 years -- since Carl Linnaeus developed his system of naming plants and animals -- researchers classified species based on visual attributes like color, shape and size. In the past few decades, researchers found that sequencing DNA can more accurately identify species. A group of single-celled algae -- Symbiodinum -- that live inside corals and are critical to their survival -- are only now being separated into species using DNA analysis, according to biologists.

Source: DNA analysis aids in classifying single-celled algae