Regeneration is one of the most tantalizing areas of biological research. How are some animals able to regrow body parts following injury? Why can't humans do the same thing? Can scientists learn the secrets that imbue certain animals with this amazing ability? Could that knowledge someday be used to develop new therapies to help people heal? Four professors in the Department of Biology — Randal Voss, Jeramiah Smith, Ann Morris, and Ashley Seifert — are undertaking the basic scientific research needed to begin to answer these and other questions. Each of them approaches the problem from a different angle, focusing on different aspects of regeneration, and using different vertebrate models. Ann Morris works with zebrafish, a minnow-like freshwater fish that has an ability to regenerate retinal cells. We humans lack that ability. Degenerative diseases of the retina — such as retinitis pigmentosa or macular degeneration — are the leading causes of blindness in older adults. If scientists can learn how zebrafish are able to repair their retinas, it could point the way to new strategies for developing treatments to preserve vision, or perhaps even to restore it, in humans. The structure of the retina and the types of cells found therein are similar across all vertebrates. By studying how the retina develops in zebrafish embryos, Morris says, researchers can learn a great deal about how the process works in mammals, and specifically in humans. An oft-repeated maxim in biology classrooms is that "regeneration recapitulates development." So, if our retinas are so similar in their development, how is it that zebrafish can regenerate retinal cells and we can't? That's an excellent question, Morris says. The answer is suspended between between two distinct possibilities. "One is that at some point, everybody had the ability to regenerate, and that ability in certain lineages was eventually lost," Morris said. "So perhaps all the mechanism is still there in the genome and it just needs to be reactivated. The other is that as these different vertebrate lineages diverged, certain vertebrates evolved that ability whereas others didn’t. I happen to believe it’s probably more of the former, that some of those abilities are there and they’re latent and we have to discover how to reactivate them." Photography by: Brian Connors Manke