A sea slug known as Elysia Chiorotica has jumped on the
green bandwagon, earning a name for itself as the first solar-powered animal. The
Elysia Chiorotica, found in eastern Canada’s
saltwater marshes, is believed to be the first animal that is able to feed
itself using photosynthesis.
As we all remember from elementary school science class,
plants turn energy from the sun into food for themselves through
photosynthesis. How is this 3-centimeter slug, which resembles a small leaf,
able to perform a function that is characteristic of only plants? Sidney
Pierce, a University of South Florida biologist, led a team of researchers that discovered just that.
Pierce and his team determined that Elysia Chiorotica did
not simply steal the chlorophyll from the algae when it fed. In fact, it only feeds
once in its lifetime from the algae before producing its own food via
photosynthesis. Other animals, including coral, can store chloroplasts in their
cells, giving themselves a sort of stolen food bank. The Elysia Chiorotica is
different.
Over millions of years, Elysia Chiorotica was able to absorb
DNA from its neighbor, Vaucheria Litorea, a
species of algae that also exists in North Atlantic
coastal habitats. The algae’s ability to photosynthesize was absorbed into the
sea slug. In the early stage of the green sea slug’s life, it eats from the
algae, taking in chlorophyll-producing cells.
But “those genes are already there, in the slug, and
transferred from generation to generation,” Pierce says. The slug’s own ability
to derive energy from sunlight is activated. It then spends the rest of its
life producing its own food with a little help from the sun.
The finding is particularly of interest because it is
the first discovery of gene transfer between multi-cellular species. While only
a preliminary step, Pierce’s findings could help drive research into gene
therapy to fight disease. Invertebrate zoologist at The Citadel, John Zardus,
says it best, “This could be a fusion of a plant and an animal—that’s just
cool.”
