ANN ARBOR—Biologists long have marveled at the ability of some animals to re-grow lost body parts. Newts, for example, can lose a leg and grow a new one identical to the original. Zebrafish can re-grow fins.

These animals and others also can repair damaged heart tissue and injured structures in the eye. In contrast, humans have only rudimentary regenerative abilities, so scientists hoping eventually to develop ways of repairing or replacing damaged body parts are keenly interested in understanding in detail how the process of regeneration works.

Using zebrafish as a model, researchers at the University of Michigan have found that some of the same genes underlie the process in different types of tissues. Genes involved in fin regeneration and heart repair are also required for rebuilding damaged light receptors in the eye, they found, suggesting that a common molecular mechanism guides the process, no matter what body part is damaged.

Zhao Qin, a graduate student in the department of Molecular, Cellular and Developmental Biology, presented the research Oct. 19 at the annual meeting of the Society for Neuroscience in Chicago. Her coauthors on the paper, which also was published in the Proceedings of the National Academy of Sciences, are professor and chair Pamela Raymond and research laboratory specialist Linda Barthel.

The researchers briefly exposed zebrafish to intense light, which destroys the light receptors in their eyes, just as staring into the sun harms human eyes. But unlike humans, who remain blinded if the damage is severe enough, zebrafish repair the damage with new nerve cells (neurons).

Where do those new cells come from? The U-M researchers suspected they develop from cells in the retina called M