Tag: Poster 76

Genetic Architecture of Local Adaptation and Reproductive Isolation in Mimulus aurantiacus

Presenter: Hanna McIntosh

Faculty Mentor: Matt Streisfeld, Sean Stankowski

Presentation Type: Poster 76

Primary Research Area: Science

Major: Environmental Science

Funding Source: UROP Mini-Grant, University of Oregon, $1000

A major goal of speciation research is to understand the genetic architecture of isolating barriers. Theoretical studies predict that isolating barriers are most effective if they have a simple genetic basis and are controlled by loci in
the same genomic regions. To test this hypothesis, we used Quantitative Trait Locus (QTL) mapping to determine the genetic architecture of floral trait divergence between red and yellow ecotypes of the monkeyflower Mimulus aurantiacus. These ecotypes are closely related, but partially isolated due to preferences of different pollinators for contrasting floral traits. We phenotyped an F2 mapping population (n=226) and used RADseq to generate a high- density genetic map to investigate two floral traits—color and size—thought to underlie preference. Using a multi- QTL model, we identified 2 QTLs for flower color and 3 QTLs for flower size. For size, the total phenotypic variation explained by the 3 QTLs was 36%, indicating that this trait is controlled by many genes of small effect. In contrast, a single QTL explained over 65% of variation in flower color. While recent studies have shown that multiple isolating traits are controlled by the same genomic region, we observed no QTL overlap for color and size. In addition to revealing the genetic basis of adaptation in M. aurantiacus, our results show that complex, simple, and genetically- independent traits can contribute to reproductive isolation early in speciation.

Asymmetry of the Dental Arcade in Six Populations from the Indian Sub-Continent 

Presenter(s): Aimee Herubin − Anthropology

Faculty Mentor(s): Jeanne McLaughlin, Frances White

Poster 76

Research Area: Physical science

Deviations from symmetry that arise during development are defined as fluctuating asymmetry (FA). Greater asymmetry is often related to differences in genetic and environmental factors experienced during development with males showing more asymmetry than females. We measured FA in human dental arcades from different Indian social castes. We hypothesized that men and women would have differing degrees of asymmetry as well as individuals in different castes. We measured samples from the John R. Lukacs Dental Cast Collection at the University of Oregon. Our sample consisted of 177 paired mandibles and maxillae (57 females, 120 males). Individuals were from one of six social castes. Permanent dentition was measured in a three-dimensional plane at the cervix between the first incisors and on the distal surface of premolars and molars. 13 landmarks were digitized using a microscribe-3DX© following the protocol of Frost et al (2003). Dental FA was measured by calculating the Procrustes’ distance between each individual and its mirror image. We compared mean asymmetry by sex and caste using a two-way ANOVA. We found significant differences in both the maxilla and mandible FA between castes (F=51.28, DF=5, p<0.0001 and F=19.40, DF=5, p<0.0001, respectively) but not between sexes with no significant interaction term. Our hypothesis that there would be a difference in asymmetry between sexes was not supported, however, our hypothesis that there would be differences in levels of asymmetry between castes was supported. This suggests that there may be genetic or environmental factors influencing dental arcade development differently in different castes.

Orthogonal Structure on a Tripod

Presenter(s): Sierra Battan

Faculty Mentor(s): Yuan Xu

Poster 76

Session: Sciences

This thesis establishes an orthogonal basis that accurately represents the structure of polynomials on any three-dimensional tripod. I define, restrict, and describe the contents of an inner product space for a corresponding orthogonal tripod. Then I explicitly construct a basis of the inner product space and study its transformation to an orthogonal basis, using many different algorithmic methods of increasing efficiency. Ultimately, my thesis extends the forefront of mathematical research in the numerical field and helps create a structure with which mathematicians can manipulate currently unmanageable monster polynomials that live in the three-dimensional world.