Biology Professor Works with Student Researchers on Zebrafish Hormone Experiment
What do zebrafish and humans have in common? If you're talking about their embryos, then it's a lot, and this is what Dr. Christopher Lassiter of the Roanoke College biology department has been researching. Lassiter, along with five students, has been looking at factors that can impact the development of hormones in zebrafish embryos.
Testing on a zebrafish embryo proves beneficial because it uses the same genes as humans to make an embryo. Zebrafish also produces multiple embryos at a time that fertilize outside the uterus, allowing researchers to see the entire process. Because fertilization occurs in the water and the embryos are transparent, Lassiter and his student researchers are able to easily treat the embryos with chemicals.
"The chemical we use is vinclozolin, which is a fungicide that's used on golf courses and crops," says Lassiter. "Because vinclozolin is an anti-testosterone it can make males more female and has shown to have had a drastic effect on mice. We're concerned with chemicals that could be impacting wildlife and humans - society is dumping all these pesticides and fungicides into the river systems and they don't get filtered, so we're ingesting them."
Part of Lassiter's research has to do with finding the testosterone receptor gene in the zebrafish and figuring out if it's similar to the one in humans. Lassiter says that he and his students have discovered that the gene is quite similar in both zebrafish and humans. In the summer of 2006, he worked with Lien-Thanh Kratzke '07 on a Summer Scholars project where they cloned the testosterone receptor gene. The following summer, he worked with Amanda Smolinsky '08, testing the vinclozolin on the embryos.
"We found that when we dumped vinclozolin in the zebrafish, they tried to compensate by making more testosterone receptors, but they could only do it to a certain point because they eventually overloaded and couldn't make enough," says Lassiter. Because he has the DNA for the receptor gene in three parts, he gets help from his students, Jennifer Doughman '09 and Carly Waterstraut '09. The two young researchers work on pasting the gene together at a molecular level so that it may be used in further studies.
Lassiter also works with the other sex hormone, estrogen. Bryan Ford '08 is working in the lab to see if risperidone, an antipsychotic drug, affects estrogen levels in the zebrafish embryo. Since the zebrafish has up to 1,000 times more estrogen in its brain than humans and can heal its brain and spinal cord better, looking at how the zebrafish uses estrogen can help researchers find possibilities for spinal repair. "My role is to work with zebrafish and lay the groundwork for people to do these kinds of things," Lassiter says.
"What I try to get through to my students is that when you analyze data and you realize that you're the first person on the planet to know something, it's a big rush," Lassiter says. "Also, being able to think independently as a scientist is important. If I can teach my students how to think critically as an independent scientist, they can acquire the skills to solve problems."
Lassiter received his bachelor's degree in biology from Furman University and his doctorate in genetics and genomics from Duke University. He has been teaching at Roanoke since 2005.