The goal of the three-year grant, which begins Aug. 1, is to create zebrafish in which a gene has been modified or permanently turned off, and the offspring inherit the alteration, said Paul Collodi, Department of Animal Sciences professor and senior researcher on the project. The progeny that possess the mutation are called knockouts. Once successfully produced in zebrafish, the knockouts will be used to study a gene's function.

The researchers are interested not just in making a genetic change, or mutation, in one fish, but also in its future generations, and more.

"The goal is to enable us to learn the role of specific genes in the zebrafish, which is an organism that is easy to study," Collodi said. "This information then can be applied to studying gene function that's involved in human disease and embryo development."

Currently knockouts are only possible in mice. Successfully duplicating the process in zebrafish would require much less time and money for researching gene function.

"The big problem in producing knockouts in species other than the mouse has been that it's been impossible to keep stem cells viable so that they contribute to the germ line, or eggs and sperm," Collodi said. "Now we have cells that we can grow for a long time in culture and they can still be transplanted into an embryo where they will become eggs or sperm."

The scientists discovered a way to keep altered embryonic stem cells from zebrafish alive long enough to pass on specific genetic changes. However they have not yet made a knockout using this technique. They currently are working to introduce a specific alteration into embryonic stem cells. It takes two generations to produce an adult fish with a specific ge
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Contact: Susan A. Steeves
ssteeves@purdue.edu
765-496-7481
Purdue University
28-Jul-2003