Chlorophyll Producing Half Plant Half Animal Sea Slug Discovered

The next time you’re in the salt marshes of New England and Canada, watch out for a little green sea slug. If you’re lucky, you’ll spot the Elysia chlorotica, the world’s first animal known to produce its own chlorophyll.

The discovery of this unique half plant, half animal sea slug, the Elysia chlorotica, is not new. In fact, according to LiveScience, biologist Sidney Pierce of the University of South Florida in Tampa has been studying these creatures for about 20 years now. His most recent findings were presented on January 7 2011 at the annual Society for Integrative and Comparative Biology meeting in Seattle and were first reported in Science News.

Pierce claims the sea slug is not born with the ability to synthesize its own food from sunlight. Instead, baby Elysia chlorotica must steal the gene needed to create chlorophyll, which was previously only known to be synthesized by plants, from the algae it feeds on. The sea slug also steals chloroplasts, or parts of a cell needed to conduct photosynthesis from the algae. Once a sufficient quantity of algae is eaten, the Elysia chlorotica will develop the ability to produce its own chlorophyll and, like any other plant, synthesize sunlight into energy-containing molecules that it uses to fuel its body.

“This is the first time that multi-cellular animals have been able to produce chlorophyll,” reports LiveScience.

Pierce and his colleagues have collected these sea slugs and placed them in aquaria for months on end. He claims that the slugs, which have heads resembling snails but bodies resembling an algae-covered soft coral, can survive without food provided that they have a light shining on them for 12 hours a day.

To make sure that the slugs are actually producing their own chlorophyll and not stealing it from the algae it snacks on, scientists have used a radioactive tracer to track the pigments. They discovered that the slugs incorporate the stolen genes so well that the ability to produce chlorophyll can be passed on to future generations. However, the slugs cannot photosynthesize energy until they’ve eaten enough algae.

Pierce and his colleagues remain puzzled as to how the slugs steal the chlorophyll-producing gene from the algae. While the slugs have proven that inter-species transfer of DNA is possible, scientists are unsure of the mechanism of the transfer.

Perhaps Crustacean biologist Gary Martin of Los Angeles’s Occidental College said it best. Mother Nature Network reports his one-word summary: “Bizarre”.