After 20 years of studying the sea slug Elysia chlorotica, biologist Sidney Pierce recently discovered a trait unprecedented in the animal kingdom - sea creatures were producing chlorophyll.
The University of South Florida researcher unveiled this discovery in Seattle at last week's annual gathering of the Society for Integrative and Comparative Biology. Pierce observed that the slugs acquired the photosynthetic DNA from their food source, algae. He spoke to LiveScience about the squishy genetic bandits' propensity to eat and run:
The sea slugs live in salt marshes in New England and Canada. In addition to burglarizing the genes needed to make the green pigment chlorophyll, the slugs also steal tiny cell parts called chloroplasts, which they use to conduct photosynthesis. The chloroplasts use the chlorophyl to convert sunlight into energy, just as plants do, eliminating the need to eat food to gain energy.
"We collect them and we keep them in aquaria for months," Pierce said. "As long as we shine a light on them for 12 hours a day, they can survive [without food]."
The researchers used a radioactive tracer to be sure that the slugs are actually producing the chlorophyll themselves, as opposed to just stealing the ready-made pigment from algae. In fact, the slugs incorporate the genetic material so well, they pass it on to further generations of slugs.
The babies of thieving slugs retain the ability to produce their own chlorophyll, though they can't carry out photosynthesis until they've eaten enough algae to steal the necessary chloroplasts, which they can't yet produce on their own.
This discovery gives me hope that somewhere deep in the human genome, some latent photosynthetic trigger will kick in if I eat 10 lbs. of kale a day. Just another reason to eat your greens, dear readers.