Emily Mowry ’24, Biology major and Creative Writing minor, shares about their internship with San Diego State University in San Diego, CA
“My research project focuses on investigating the molecular mechanisms of X chromosome dosage compensation and testing candidate regulators in the Drosophila model system using various techniques, including genetic, molecular, and microscopy methods. The project involves two main parts: first, I cross existing mutations with an established dosage-compensation complex to identify novel regulators that control dosage compensation levels in male flies. Secondly, I examine a known regulator called Megator and its impact on epigenetic marks by crossing Megator RNAi with En-Gal4 and nub control strains, dissecting and staining tissues, and analyzing the data obtained through immunofluorescence on a high-resolution microscope.
On a daily basis, my tasks include breeding, caring for, identifying, and counting drosophila flies. I prioritize my tasks based on available food vials and any urgent schedule items. If food vials are low, I create a new batch of fly food and work on the flies in the meantime. Preparing, making, and distributing the food into new vials takes about 2 hours, with an additional 24 hours for the agar to cool.
I start each day with virgin collections of rox1^Ex33 rox2Δ and rox1^Ex6 rox2Δ stocks, of which I have 100+ vials, using CO2 to immobilize the flies for sorting based on gender and phenotypes. Virgins are identified by a black mark on the abdomen, usually near the hip, caused by undigested food, indicating recent emergence from the pupa. After sorting and identifying female virgins, I separate the ones I want for crosses while the remaining flies are put into labeled vials for breeding. Following this, I move on to virgin collections of En-Gal4, nub control, and nub-Gal4 flies.
Maintaining my fly stocks involves flipping vials around once a month to ensure their vitality and 
prevent contamination. Flipping the flies means shaking all the flies from one vial to into a new vial. To expand stocks, I flip vials weekly. When flipping flies, it’s essential to consider the vial’s condition to avoid issues like “dead vials” with continuously dying flies, dirty vials with old and dead flies at the bottom, infected vials, or overly aged vials. Daily checks involve monitoring food levels, larvae condition, and humidity. Adding a small amount of water is necessary if the food becomes too dry. Particular attention is given to vials intended for upcoming crosses. Daily checks of around 400+ vials are necessary, ensuring sufficient food, monitoring larvae, and maintaining proper conditions.
Cross scoring is another essential part of my work, involving regular checks of cross parents to refresh the crosses if needed. Timing is crucial to avoid contamination from parents or potential cross contamination with the F2 generation as only the F2 generation is needed. Data is not recorded after 20 days to prevent F2 contamination. Three types of crosses are running, each with multiple vials, the first cross involves rox1^Ex33 rox2Δ and rox1^Ex6 rox2Δ female straight wing virgins with male w^1118 (wildtype). Next I move on to cross scoring En-Gal4, nub control, and nub-Gal4 crosses, each crossed with mtor RNAi (II) and mtor RNAi (III), consisting of approximately 10 vials so far.The final step involves analyzing mutant crosses (around 84 vials) to examine the impact on male lethality and record gender, phenotypes, and the influence of balancers used in the crosses. Data collection includes recording gender, phenotype (e.g., eyes and wings), and the impact of the balancer used in the crosses, which influences the phenotype in various ways.
I prioritize collecting virgin flies hourly to secure specimens and minimize cross contamination. Cross scoring is done every two hours to ensure accurate results. In my downtime, I study fly identification, read articles, plan future crosses, and transfer data from my lab book to a Google spreadsheet for analysis. In addition to my regular tasks, my days involve making extra fly food, engaging in discussions with peers and superiors about projects and to deepen my understanding of the subject, and work on upcoming assignments for WIG.
This internship has been a valuable experience, combining my passion for biology and creative writing in a research environment that has expanded my knowledge and skills in epigenetic regulation and Drosophila genetics.”