Dlugosch Lab, University of Arizona
We love to involve undergraduates in our lab’s research, and we frequently develop independent projects with students that are excited by the work that we do. Interested students should contact Dr. Dlugosch or any of the people in the lab whose research particularly captures your enthusiasm.
We gladly accept students under the following arrangements:
1) Course credit (Independent Study or Directed Research, including Honors). This requires a specific time commitment for the number of credit hours received. This is the most common way that students join the lab.
2) Internships from Pima CC or other programs. We have had several great Pima interns, and we encourage inquiries from students looking to fulfill formal internship programs.
3) Pay. We do have occasional openings for student employment, including through the UA UBRP program, and we are often looking for folks with Federal Work Study (FWS) aid. We typically advertise open positions to the Biology undergraduate list, but we especially encourage UBRP and FWS students interested in our research to get in touch with us.
4) Volunteering opportunities in the lab are more limited. We prefer to make a more formal commitment through course credit, so that both the student and mentors in our lab get the most out of the experience.
Recent Examples of Undergraduate Research
2018 Honors Theses
Advised by: Alice Cang, Katrina Dlugosch
Species invasions can be influenced by various ecological and genomic factors. One contribution that may influence the ability for new variation to arise comes from transposable element (TE) activity. TEs may provide organisms with favorable novel genomic mutations that allow for adaptation. This study investigates the contribution of TE content in Centaurea solstitialis, commonly known as yellow starthistle (YST). YST is known for its invasive ability in the Americas, where it has established large invaded ranges. In this study, seeds from native and invaded populations were reared in a common environment and traits involving growth, reproduction, and genome size were measured. Correlations between genome size and growth rate, dry aboveground biomass, number of flowering heads, and days to first start flowering were tested. In addition bioinformatic analysis of genomic data from a native and invading YST were used to estimate average number and average length of long terminal repeat (LTR) sequences. Results from genomic analysis show substantial amounts of intraspecific size variation in genomic content, commonly attributed by class I TE activity, as well as larger genome size being positively correlated with longer development times. These results demonstrate that TE activity contributing to genome size correlates with important ecological traits.
Advised by: David Hembry, Katrina Dlugosch
The purpose of this study is to look at the evolution of growth form and invasiveness in leafflower plants (Phyllanthaceae: Phyllantheae: Phyllanthus sensu lato) using phylogenetic and comparative methods. Most species of Phyllanthus are woody but some species are herbaceous, and taxonomy indicates that this transition may have evolved multiple times. We use a publicly available dataset from Kathriarachchi et al., 2006 and attempt to augment the existing data set with DNA sequenced from dried leaf samples of weedy and invasive species. Using phylogenetic approaches and ancestral character state reconstruction, we ask the following questions: (1) Has the transition between herbaceousness and woodiness evolved multiple times in Phyllanthus s. l.? (2) What is the ancestral growth form state for Phyllanthus s. l.? (3) Have globally-distributed weedy/invasive species in Phyllanthus s. l. evolved once, or independently multiple times? Ancestral character state reconstruction indicates that the ancestral growth form state for Phyllanthus s. l. is woodiness and that most transitions have been from woodiness to herbaceousness. Results demonstrate that herbaceousness has evolved about six times and that invasiveness has evolved more than once in the genus Phyllanthus s. l.
Joseph Aspinwall & Ashley Davis
Advised by: Angela Kaczowka, Pat Lu-Irving, David Baltrus, Katrina Dlugosch
Summary: Yellow starthistle (Centaurea solstitialis) is an annual plant species native to regions of Eurasia that was introduced to the Americas and has become invasive in grassland regions of the United States. In regions of infestation, it lowers forage yield, disrupts livestock grazing and reduces economic value.
Invading plants may be benefiting from escape from pathogens and have evolved greater investment in growth and reproduction. The “oxidative burst” is one of the main responses to pathogen infections and can reveal evolution in plant-pathogen interactions. Peroxidase is a crucial part of ROS production in the oxidative burst. Using a high throughput peroxidase assay, we test for evolution of the immune response to bacteria in native and invading populations.
Advised by: Shana Welles, Pat Lu-Irving, Katrina Dlugosch
Summary: Yellow starthistle (Centaurea solstitialis, Asteraceae) is a native
species of Eurasia that was introduced to western North America in the 1800s, where the population has grown to high abundance. The goal of this research was to independently assemble the genome of a native individual from Turkey and an invasive individual from California.
Advised by Joseph Braasch, Katrina Dlugosch
Summary: Habitat disturbance often creates favorable conditions for invasive plants. Erodium cicutarium, a non-native species in the Sonoran Desert, has become increasingly common in long term study plots and is abundant in grazed rangelands. Erodium cicutarium shown to have a higher relative growth rate and to out-compete its native congener Erodium texanum in a common garden. At Tumamoc Reserve, E. cicutarium appears to be more abundant in disturbed areas, while E. texanum appears to be more abundant in undisturbed areas. We hypothesize that Erodium cicutarium (Non-native) will have a higher growth rate and produce more fruit in disturbed habitat, and Erodium texanum (Native) will have a higher growth rate and produce more fruit in undisturbed habitat.