Genevieve Croft

Ph.D. Candidate
Evolution, Ecology, and Population Biology Program, Washington University

Co-Advised by Dr. Barbara Schaal & Dr. Peter Raven

CV
croft[at]wustl.edu

A range of experiences have shaped my approach to the study of ecology and evolution. Chief among them were two years with the Peace Corps in a small farming village in central Panama.

For my dissertation research, I focus on a cultivated species I first came to know in Panama, using it to explore unresolved concepts in evolution and ecology.

Thesis Research

"Genetics and ecology of early domestication in Byrsonima crassifolia (L.) Kunth"

Byrsonima crassifolia (L.) Kunth, Malpighiaceae, locally known as "nance," among other names, is a Neotropical fruit tree that occurs from Mexico to Brazil. It is cultivated in home gardens and collected from wild populations for local sale and consumption throughout much of its range. It is occasionally cultivated in orchards, particularly in Mexico. In some regions, this history of use by humans goes back several thousand years, although it does not yet display definitive characteristics of a "domesticated" species.

For my dissertation, I am investigating the genetic and ecological impacts of human management of plants on this "incipiently domesticated" species. I have collected nance from home gardens, pastures, savannas and forests in Bolivia, Brazil, Mexico and Panama. I have developed eight microsatellite markers for this species, and have begun using them to evaluate whether people have influenced the genetic diversity of populations of this plant. I will combine these genetic data with a comparative modeling study of the ecological distributions of wild and cultivated plants to learn more about how people influence plants in the early stages of domestication.

Graduate Rotation Projects

"Molecular Phylogeny of Claytonia ozarkensis"
With Barbara Schaal and George Yatskievych

Claytonia ozarkensis (Montiaceae) is a spring ephemeral that was first described by Miller and Chambers in a 2006 monograph. It is reported to occur only in the Missouri, Arkansas and Oklahoma Ozarks, although at this time, contemporary populations have been located only in Arkansas. During my research rotation in the Schaal lab, I collected samples from the field, and we received samples of related species from colleagues and nature enthusiasts around the country. We have sequenced these samples at three neutrally evolving loci. We are using these data to investigate the relationship between C. ozarkensis and its close relatives, and to begin to document the molecular diversity within C. ozarkensis.

"Optimizing microsatellite loci for Crotaphytus collaris collaris"
With Alan Templeton and Jennifer Neuwald

In the fall of 2006, I worked to optimize microsatellite loci for Dr. Alan Templeton's long-term population genetics study of a group of Eastern collared lizards.

"Morphological and demographic change in a founder population of the eastern collared lizard"
With Alan Templeton

In the spring of 2007, I continued work on the collared lizard project, analyzing six years of data following a founder event. Collared lizards had gone locally extinct due to fire suppression at the Peck Ranch Conservation Area in southeastern Missouri. In the 1980s, several individuals were released on Stegall Mountain following the reinstitution of a fire regime. As the area of controlled burns increased, glade habitat on nearby Thorny Mountain opened up, and several individuals were discovered there in 2001, where none had been before. I looked at morphological and demographic data collected on Stegall and Thorny individuals in the years following this event to see if any changes could be detected. We hypothesized that the low population size that has resulted in neutral allele frequency differences between the two mountains could also affect phenotype as measured by size characteristics. In addition, altered demographic pressures in the new region could impact hatchling sex ratios.