Anthropology - Butler University

Dosage-sensitive genetics is a powerful tool for understanding relationships between genes. By
creating flies with null and hypomorphic alleles, the expression levels of particular genes can be
reduced. We took Drosophila with chromosomal deletions spanning the entire second
chromosome and bred them into the hypomorphic Trio and Abl gene backgrounds. Trio, a
guanine-nucleotide exchange factor, and Abl, a tyrosine kinase, are each involved in a common
signal transduction pathway during the process of axon outgrowth during neuron development
(Liebl et al., 2000). In flies that had a gene deletion in a region having genes involved in the
Trio or Abl regulatory pathway we expected to see a lower survival rate. Performing pupae and
adult counts on these deficient flies in hypomorphic backgrounds, we found several gene regions
and potential genes of interest. Once broad regions of interaction were established, we worked
with narrow subdivisions in order to further close in on which specific gene regions might be
interacting with Trio and Abl. These results will provide insight into a more complete
understanding of axonal growth and has potential to further develop our general model for
protein signaling cascades and cell response.
Investigating the Factors Influencing Migration Orientations of the Wood Frog (Lithobates
sylvaticus)
Mark Magnus, Faculty Sponsor: Rebecca Homan, Denison University
In a study conducted by Homan et al. (2010), it was found that juvenile wood frogs (Lithobates
sylvaticus) dispersed away from their natal pond in a non-random direction each year, but the
direction changed across years. Due to the fact that the study site was a stable environment, the
orientation cues utilized by dispersing juveniles must have had the potential to change across
years. In this study we wanted to test our hypothesis that juvenile wood frogs would detect and
orient toward chemical cues deposited by conspecifics while leaving the pond. We performed Y-
Maze trials in which juveniles could choose to move toward an arm marked by conspecifics or
toward an arm without chemical cues. The results of our study showed that more juveniles made
a choice than did not, meaning our experimental design was effective. However, we were unable
to find any influence of body size, date of capture, or the direction the juveniles were oriented on
the frequency of arm choice. We did find that North-bound frogs significantly chose the positive
over the negative arm and that South-bound frogs tended to do the opposite. The total number of
juveniles captured throughout the season was lowest in the North and greatest in the South,
possibly suggesting a density dependent orientation strategy. By increasing sample sizes in
future years of this study we hope to determine whether these preliminary patterns continue in
years in which the North and South are not the least and most frequent orientation directions,
respectively.
A Preliminary Study of the Secretory Mechanism of the Venus Flytrap (Dionaea
muscipula): Do Carnivorous Plants Have Apocrine or Merocrine Glands?
Caroline Matchett, Faculty Sponsors: Matthew Collier & Kevin Gribbins, Wittenberg University
The Venus flytrap (Dionaea muscipula) is highly specialized and unique in its method of nutrient
procurement. Flytrap leaves close rapidly in response to prey items coming in contact with
trigger hairs located on the leaf epidermis. Upon closure, glands on the leaf surface secrete
proteolytic enzymes that digest prey over the course of 5-12 days. Although the mechanism of
flytrap leaf closure is well described, the secretory nature of the digestive glands remains poorly