Two new laboratories in plant ecological and evolutionary genetics are seeking suitable candidates to pursue PhD degrees at the University of Tennessee in Knoxville.
Graduate studies in plant ecological genetics at the University of Tennessee
Ecological genetics is a broad field in evolutionary biology dealing with the genetic basis of ecologically relevant traits in living organisms. It has a complex history and is currently an exciting area of research where organismal and molecular biologists can interact. Projects in ecological genetics offer a unique opportunity for combining field and laboratory studies, learning about the use of molecular markers in ecology, about multivariate statistical analyses, and about modern evolutionary quantitative genetics. Two new laboratories conducting studies in plant ecological genetics have recently been established at the University of Tennessee in Knoxville, which already has a long tradition of activity in plant ecology. A brief description of the research programmes currently undergoing in these labs follow. We are interested in attracting bright and motivated students to our PhD program in the Departments of Botany and of Ecology and Evolutionary Biology.
Massimo Pigliucci (PhD, University of Connecticut). Genetics and evolution of plants' responses to environmental changes. My primary interest is in the genetics and evolution of plants' reaction to changes in environmental conditions, often referred to as phenotypic plasticity. In general, however, I am interested in the study of the evolution of multivariate (whole-organism) phenotypes. The work that is currently ongoing in my lab uses the mustard weed Arabidopsis thaliana as a model system, and investigates the regulatory genes responsible for sensing alterations in light quality associated with the competition regime. I am also looking at the evolution of plasticity in this genus, applying comparative methods based on a known phylogeny derived with the use of molecular markers The objective is to reconstruct the changes in the plants' ability to react to environmental stimuli during the transition from high-altitude environments, typical of the ancestral species in the group, to the low-altitude environments, characteristic of more recently derived taxa. Dr. Hilary Callahan will be joining my lab in 1996 as a postdoctoral associate studying natural selection on plasticity in wild populations of A. thaliana in Tennessee. In addition to the Arabidopsis system, there are a number of species that occur in this region (particularly in the Great Smoky Mountains and the Cumberland Plateau) that would be ideal experimental organisms for the study of phenotypic plasticity and, more in general, ecological genetics.
Examples of recent publications:
Pigliucci, M. and C.D. Schlichting. 1995. Ontogenetic reaction norms in Lobelia siphilitica (Lobeliaceae): response to shading. Ecology 76:2134-2144.
Pigliucci, M. and C.D. Schlichting. Reaction norms of Arabidopsis. III. Geographic variation and response to nutrients in 26 populations. Am. J. Bot. 82:1117-1125.
Pigliucci, M., C.D. Schlichting, and J. Whitton. 1995. Reaction norms of Arabidopsis. II. Response to stress and unordered environmental variation. Funct. Ecol. 9:537-547.
Pigliucci, M., J. Whitton, and C.D. Schlichting. 1995. Reaction norms of Arabidopsis. I. Plasticity of characters and correlations across water, nutrient and light gradients. J. Evol. Biol. 8:421-438.
Schlichting, C.D. and M. Pigliucci. 1994. Gene regulation, quantitative genetics, and the evolution of reaction norms. Evol. Ecol. 8:1-15.
Mitchell B. Cruzan Departments of Ecology and Evolutionary Biology / Botany
Genetic marker approaches to plant evolutionary ecology. My students and I are working on a variety of questions in plant population biology. Ongoing projects in the lab include: 1) analyses of plant mating interactions that encompass the areas of pollination biology, pollen-pistil interactions, and mecahnisms affecting variation in the proportion of selfed and outcrossed progeny; 2) the structure and dynamics of hybrid zones using genetic marker techniques in field and lab experiments, and 3) the use of linkage mapping procedures to examine the genetic architecture of inbreeding depression and its population cosequences under field and lab conditions. In these projects we endeavor to integrate field studies with lab analyses using allozyme and PCR-based genetic marker techniques, microscopy, and computer-aided video image acquisition and analyses. Our studies of species in the local region and in Florida touch on issues in evolutionary biology, ecology, and conservation biology.
Examples of recent publications:
Cruzan, M.B. and M.L. Arnold. 1994. Assortative mating and natural selection in an Iris hybrid zone. Evolution 48:1946-1958.
Cruzan, M.B. and M.L. Arnold. 1993. Ecological and genetic associations in an Iris hybrid zone. Evolution 47:1432-1445.
Cruzan, M.B. J.L. Hamrick, M.L. Arnold, and B.B. Bennett. 1994. Mating system variation in hybridizing irises: effects of phenology and floral densities on family outcrossing rates. Heredity 72:95-105.
Cruzan, M.B. and S.C.H. Barrett. 1993. The contribution of cryptic incompatibility to the mating system of Eichhornia paniculata (Pontederiaceae). Evolution 47:925-944.
Cruzan, M.B. 1990. Variation in pollen size, fertilization ability, and postfertilization siring ability in Erythronium grandiflorum Evolution 44: 843-856.
Affiliated Faculty
Chris Boake, Department of Ecology and Evolutionary Biology (Behavioral ecology, Quantitative genetics). Sergey Gavrilets, Department of Mathematics (Population and Quantitative genetics). John Gittleman, Department of Ecology and Evolutionary Biology Systematics (Phylogenetic inference, Comparative methods). Gary McCracken, Department of Ecology and Evolutionary Biology (Mating and hybridization in animals, Conservation biology).
Ed Schilling, Department of Botany (Plant systematics).
The Knoxville Area
The city of Knoxville and vicinity provide a congenial environment for graduate studies in plant ecological genetics. As a medium-sized city (250-300 thousand), Knoxville possesses a cultural diversity that rivals much larger metropolitan areas. There is a variety of musical formats and performing arts available including very active Jazz and folk music scenes, several classical organizations, ballet, and opera. One of the more attractive features the university is the ease of access to local natural areas including the Smoky Mountain National Park, the southern Appalachian and Cumberland Mountains. It is possible to live in a relatively rural setting and still be within minutes of campus. The low cost of living and numerous recreation opportunities complement the excellent graduate programs in biology at the University of Tennessee.
