Emory Report

October 26, 1998

 Volume 51, No. 9

With biologist Fritz, Emory jumps into zebrafish pool

Biologists have found a new genetic development model--zebrafish. This small aquarium fish originating in India makes a better model for researching development than more traditional animals like mice and fruit flies because the study of their genes yields parallel results to human models.

Emory scientists decided to add a zebrafish facility, said Associate Professor of Biology Steven L'Hernault, "because in the area of genetics and development, zebrafish looked like an extremely promising system." Once faculty decided to hire a zebrafish researcher, the search committee recruited developmental biologist Andreas Fritz to fill one of the facility's two positions.

Fritz, who comes from the University of Oregon, home to the largest zebrafish research facility in the world, "is an excellent geneticist [and] an imaginative geneticist who has already contributed to the development of genetic tools for the study of zebrafish," said biology Chair John Lucchesi.

Zebrafish lay numerous eggs that are clear and can be studied under the microscope, allowing researchers to follow embryonic development from the moment of fertilization. The fish's genes can be mutated or deleted, and researchers can study the impact.

Fritz said his research poses the question, "What molecules or genes specifically are involved in regulating [development] and making and imparting decisions that some cells decide to do something different from their neighbors?"

To find an answer, the biologist has developed lines of fish that have changes or subtractions in their DNA. "Ultimately what you have at hand is a particular gene within the genome, and you can assess its function molecularly as well as functionally by looking at animals in which the gene has been made defective," Fritz said. "Genes do form a large part of who we are, and if you want to understand how biological systems work, you need to address many things, but certainly genes are a large part."

Scientists can cause mutations in male zebrafish by feeding them chemicals called mutagens or by irradiating their sperm with X-rays. Certain mutagens tend to cause small changes, or point mutations, in the DNA, while X-rays tend to delete large chromosomal sections. After breeding a series of mutations in both male and female zebrafish, Fritz ends up with embryos that carry mutated genes from both parents.

The biologist currently maintains several lines of mutant fish, some of which were generated at Oregon. Currently he is collaborating with Bruce Riley of Texas A&M University in a study involving mutants for the gene msxB, which is considered important in controlling the development and complexity of the nervous system in vertebrates.

Fritz has just received a grant from the National Institutes of Health as well, and he'll begin collaborating with Marnie Halpern of the Carnegie Institute to generate and characterize numerous lines of "deletions mutants" that will be used to form a zebrafish genetic map.

Beyond his research duties, Fritz is charged with directing the formation of the new zebrafish research facility, a process he admits has been slow and sometimes frustrating but now appears complete. His teaching duties begin in the winter but he voluntarily lectures in some graduate classes. Fritz also has queried several graduate programs to begin the search for graduate and postdoctoral students.

The pool of zebrafish researchers is quite small and leads to vigorous competition for high quality students, Lucchesi said. Ultimately, he hopes Emory's entry into the field will attract such candidates. "The outlook for graduate students is good, simply because the model system is getting good press," he said.

--Paul Thacker

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