Mother Nature is always on the cutting edge of green technology. Elysia chlorotica is a type of sea slug that lives along the Atlantic coast of the US. What sets it apart from most other sea slugs is its ability to run on solar power. It has been known for some time that these sea slugs acquire and store chloroplasts from the algae they eat. In fact, young sea slugs that eat nothing but algae for 2 weeks can store up enough chloroplasts to survive the rest of their lives (about 1 year) on sunlight alone. But there's a catch... Chloroplasts only contain enough DNA to encode about 10% of the genes needed to keep themselves running. The other necessary genes are found in the algae's nuclear DNA. So until recently the question has been, how do the chloroplasts continue to function in a slug cell that is missing 90% of the genes necessary for it to function. Recent studies performed at the University of Maine suggest that the sea slug may be able to steal some of the algae's DNA along with its chloroplasts. When the researchers sequenced the sea slug's DNA, they found that it had incorporated one of the algae's genes that is necessary for chloroplast function. The scientists aren't sure how the slug is able to incorporate the algae's DNA. One possibility is that, as the algae are digested in the slug's gut, the gene is taken into its cells as along with the chloroplasts. The genes are then assimilated into the slug's own DNA, allowing the animal to produce the necessary proteins for the stolen chloroplasts to continue working. Another possibility could be that a virus found in the sea slug will take up the DNA from the algal cells and transmit it to the sea slug's cells. There is still much to learn about how the sea slugs acquire and use the algae's genes and chloroplasts. What is clear (to me, at least) is that nature is cool.
