Stories tagged slugs

Jan
28
2010

Elysia chlorotica: You think you're so special, don't you?
Elysia chlorotica: You think you're so special, don't you?Courtesy lauredhel
Some of you may already know my feelings on mollusks. In short, I’m against them.

It’s not that I necessarily want them all exterminated, or anything. It’s just that mollusks, with their tentacles and beaks and pseudopodia and large brains, freak my Schmidt out. And I tend to live under a “you’re either with us or against us” credo, and mollusks obviously aren’t “with us.” (They aren’t with me, anyway. Frankly, most things aren’t.)

But I get by. I know that there are mollusks out there, doing… I don’t know what. Probably something utterly horrible. But we leave each other alone, and more or less leave it at that. It’s a workable arrangement.

Now and again, however, a mollusk stretches its squishy neck out and, by its very existence, makes cracks in the already fragile JGordon/Mollusca peace. It’s like the cold war, really—if one side does something strange, or develops a fantastic new piece of technology, the other side gets a little nervous. So, naturally, I’m a little cagey about this news:

There’s a marine slug (a mollusk, of course, that feeds itself through photosynthesis.

Are you kidding me? I’m all, “I think I’ve got chronic anxiety!” and this lousy slug is like, “That’s too bad. Also, I feed myself with sunlight.” I can’t even get groceries because my car battery died (there’s a very scary tree near my bus stop, so that’s out), and this little jerk is a phototroph. If I had laser eyes, or something, the situation would be a little more balanced, but last time I checked I didn’t have laser eyes.

I have to give it to the slug, though—it’s a pretty neat trick. Early in its approximately one-year-long lifecycle, the slug eats some photosynthetic algae. From that point on, the slug is photosynthetic; it feeds itself by using sunlight to convert CO2 and water into sugar, just like plants do. What’s more, the photosynthesis isn’t being performed by algae inside the slug (some organisms, like lichen contain algae, which feeds them). The slug itself has genes for photosynthesis, and the photosynthesizing genes from the algae are just required to kick-start the slug’s own abilities. And then, BAM, a photosynthetic animal.

The leaf-shaped slug, which lives in salty swamps in Eastern Canada and grows to be about an inch long, is remarkable not only for its photosynthetic abilities, but also for something unique in the process written above. Getting those kick-starting genes from the algae requires gene transfer. Passing genes from one species to another is a rare and complicated thing, but some microscopic, single-celled organisms have been known to do it. This is the first time gene transfer has been observed between two multi-cellular organisms (the slug and the algae, of course).

Aside from being, well, just sort of weird, the slug’s gene transferring abilities might turn out to be useful in the future of gene therapy, where new genes are inserted into cells to combat diseases. A practical application whatever transferring mechanism the slug and algae use is a long way off, though. And, anyway, I’ll be damned if I ever use anything that came from a mollusk.