CLARKSVILLE, Tenn. – The Braun’s rock-cress is a strange-looking little plant with star-shaped hairs covering its stems and leaves. It grows almost exclusively in the shade, usually around rock outcroppings in forests, and if you were to happen upon it, you might mistake it for a weed.
The odds of you finding a Braun’s rock-cress, however, are extremely rare. The peculiar plant is only found in two areas of the world, and in the mid-1990s, it was listed as a federally endangered species. Earlier this year, the Tennessee Department of Environment and Conservation awarded APSU professor of biology Dr. Carol Baskauf a $10,000 contract to study the population genetics of the plant species, and her research may provide valuable information aiding efforts to protect this plant.
Baskauf explained that there are various ways genetic information is useful in conservation management decisions for rare species. Due to limited funds, conservationists often have to make choices about which populations of an endangered species to preserve, and one factor they may take into consideration is genetic variability. Low levels of genetic variability might make a species more vulnerable to extinction, so it is important to preserve as much of the species’ diversity as possible. Information about which populations have the highest diversity and how genetically different populations are from each other can be useful in determining which populations to prioritize for protection, as well as helping with other management decisions such as determining which populations would be the best seed sources for starting new populations, or whether cross-pollination between plants from different populations would be likely to result in offspring with higher levels of genetic variability.
One thing conservationists wanted to know was whether Tennessee plants were genetically different from Kentucky plants.
“You have this big gap between the populations,” Baskauf said, pointing to a map showing the species’ distribution. With the Tennessee and Kentucky populations separated by at least 120 miles, it would be very unlikely for pollen or seeds to move between the two states, which in turn would make it more likely that plants from the two states could be genetically different. But when her graduate student, Nacole Jinks (2009), looked at allozyme genes in plants from both states, she found they were nearly identical. In fact, Braun’s rock-cress had less genetic variability than any other rare species that Baskauf had ever studied.
“It was quite interesting and surprising,” Baskauf said. “I expected the species to have more genetic variability than that.”
But Baskauf knew that allozyme genes are often less variable than some other genetic markers, such as microsatellites – a type of genetic marker that she had been wanting to learn to use. “Microsatellites are a type of genetic marker that tends to have a lot of variability in many species.”
So last spring, Baskauf took a semester off of teaching, thanks to an APSU Faculty Development Leave Award, and headed to Vanderbilt University to learn how to use microsatellites in the lab of Dr. David McCauley. In the process she found that there are some major genetic difference between the Tennessee populations and the Kentucky populations of Braun’s rock-cress, and even some differences among the Tennessee populations.
Her findings are due to TDEC this December, where they will contribute to conservation management plans for this endangered species. But an added benefit of her research, Baskauf said, is that she can now teach her students how to work with these highly variable and informative microsatellites.
“We encourage biology students to do research projects,” she said. Learning to use new genetic markers such as microsatellites provides me with more tools and more flexibility for my own research as well as for research with APSU undergraduate and graduate students.”
For more information on Baskauf’s work with TDEC or microsatellites, contact her at firstname.lastname@example.org.