I learned this morning from Professor Günther Zupanc that a teleost fish can grow a new backbone if you cut it in half. I used to do this to earth worms in my sandbox as a child (does that make me a candidate for the certifiable category?), and marvel at the fact that it didn’t kill them. But earthworms don’t have backbones…or any bones for that matter. It’s not a real biological feat to grow new skin cells — we do it all the time.
No, this special skill of the teleost fish is a testament to its evolutionary savvy. Fish in general can regenerate neurons very well, said Zupanc. But this species is particularly good at it because of an ancient predatory relationship, which Zupanc explained to me:
It’s very interesting from a biological point of view. They live in South America and these creatures, unfortunately, they have predators that specialize on eating their tails and in the tail is part of the spinal cord. So basically they lose part of the spinal cord all the time and in order to survive they have to be able to regenerate. So they regrow their spinal cord and these other beasts — they eat part of the spinal cord all the time.
Mammals have a much harder time growing new neurons in general, and growing new neurons in the spinal cord is especially difficult. If humans were able to regenerate spinal cord cells like teleost fish, it would mean healing from a broken neck in about eight weeks. Zupanc’s mission is to better understand neuronal systems that are good at generating new cells in order to understand those that are not so good at it — like ours.
Here’s a video Zupanc’s lab put together to illustrate the regrowth process. For more info, visit his website here.