Sea-slugs that photosynthesize have stolen DNA

New Scientist - Solar Powered Sea Slug harnesses stolen plan genes

Few creatures use the sun to provide energy, but the elysia chlorotica sea slug is one of them. The slug can survive on the energy from photosynthesis for a whole year by eating algae for two weeks. It takes the chloroplasts from the algae, but chloroplasts don't have enough DNA inside them to keep themselves alive, e.g. create the proteins to replenish themselves. The rest of the needed DNA was found when the slug's DNA was sequenced-- evidence that the slug 'stole' plant DNA.