Green Sea Slug Is Part Animal, Part Plant

It's easy being green for a sea slug that has stolen enough genes to become the first animal shown to make chlorophyll like a plant. Shaped like a leaf itself, the slug Elysia chlorotica already has a reputation for kidnapping the photosynthesizing organelles and some genes from algae.

Now it turns out that the slug has acquired enough stolen goods to make an entire plant chemical-making pathway work inside an animal body. The slugs can manufacture the most common form of chlorophyll, the green pigment in plants that captures energy from sunlight.