Department of Biology

Current Graduate Students

Afia Agyeman-Andoh

Afia Agyeman-Andoh

Thesis research topic: Primary cilia in glioblastoma tumorigenesis
Mentors: Elena Silva, Dr. Desmond Brown
Email: aa2523@georgetown.edu
 Afia is a PhD candidate working in Dr. Desmond Brown’s lab at the National Institutes of health (NIH). She graduated from Virginia Commonwealth University in 2013 with a B.S. in Biology and a minor in chemistry. She is currently working on discovering novel therapeutics for glioblastoma (GBM) -the most common primary malignant CNS.
 Outside of lab, Afia enjoys learning the Akan language, being in nature and spending time with family and friends.

Arifa Ahsan

Arifa Ahsan

Thesis Research Topic: Developmental neurobiology and regenerative processes
Co-Mentor: Dr. Elena Silva and Dr. Jeffrey Huang.
Regents Hall Science Center, 401/411A
Email: asa135@georgetown.edu
Arifa graduated from Brandeis University in 2015 with a B.S. in Biochemistry. Her undergraduate thesis at the Hedstrom Lab focused on protein degradation via small molecule hydrophobic tagging, and she designed compounds to target Bcr-Abl protein, the pathophysiological cause of chronic myelogenous leukemia. Following college, she was involved in a project on chromothripsis with David Pellman’s group at Dana-Farber Cancer Institute. (Chromothripsis is a newly discovered mutational phenomenon in certain cancer cells, characterized by extensive genomic rearrangements.) For her graduate work at Georgetown, she has decided to pursue her long-term interests in developmental neurobiology and regenerative processes and will be co-mentored by Dr. Elena Silva and Dr. Jeffrey Huang.
Outside the lab, she enjoys theatre, books, art, and creative writing.

Shahad Alqahtani 

Shahad

Thesis Research Topic: Gene expression patterns in Staphylococcus aureus
Mentor: Dr. Shaun Brinsmade.
Regents Hall Science Center, 301/311A
Email: saa354@georgetown.edu
Shahad Alqahtani comes to us from Jeddah, Saudi Arabia. She earned her B.S. in Microbiology from King Abdulaziz University in 2012 and subsequently her M.S. in Cellular and Molecular Regulation at St. Louis University. Her M.S. thesis research focused on Group B streptococcus (GBS) and its reliance on glutathione to defend itself against reactive oxygen species (ROS). Shahad recently received a scholarship from the Kingdom of Saudi Arabia to pursue her Ph.D. in the Brinsmade lab, where she will focus on CodY’s role in activating the SaeR/S Two Component System. When not in the lab, Shahad enjoys walking, cooking, and dancing with her son and baby daughter.

Vanessa V. Angelova

Thesis Research Topic: Immune responses to Giardia lamblia.
Mentor: Dr. Steven Singer
Regents Hall Science Center, 201
Email: vva5@georgetown.edu
Vanessa is a PhD candidate in the Singer lab. She graduated with a B.S. in Biology from the University of Chicago in 2018. At Georgetown, she’s been focusing on the disruption of the epithelial barrier in response to Giardia infections. This process has been extensively demonstrated in culture and in animal and patient studies, but the mechanisms behind it need further study.
She spends her free time knitting, drawing, and impatiently waiting for the next Formula 1 race. 

Sylvia Min Arnold

Sylvia Min

Thesis Research Topic: Cellular responses to environmental conditions in Candida albicans
Mentor: Dr. Ronda Rolfes
Regents Hall Science Center, 301/311A
Email: sm3313@georgetown.edu
Sylvia graduated with a B.S. in Biology from the University of Maryland, Baltimore County in 2017 where she worked in Dr. Erin Green’s lab for two years. During her time there, she worked on characterizing Set5, a yeast histone methyltransferase. After graduating, she joined the Rolfes lab at Georgetown University and is currently working on understanding the yeast transcription factor Grf10 and its role in virulence of Candida albicans. In her spare time, she enjoys spending time with her friends and family, baking, and trying new foods!

Charles Minsavage-Davis

Charles Minsavage-Davis

Thesis Research Topic: Community Genetics.
Mentor: Dr. Gina Wimp
Email: cd1231@georgetown.edu
Charles is currently a PhD student in Dr. Gina Wimp’s lab, studying plant-insect interactions. Before coming to Georgetown, he earned a B.S. in Environmental Science and an M.S. in Ecology and Restoration at Ohio State while pursuing international research in Fire ecology based in Scotland and Norway.
In his free time, he enjoys exploring and hiking with his partner and their dog.

Meghan Bullard

Meghan Bullard

Thesis Research Topic: Experience-dependent synaptic plasticity
Mentor: Dr. Haiyan He
Email: mrb339@georgetown.edu
Meghan graduated from Furman University in 2021 with a double major in Biology and German Studies. At Furman, she worked in the Freeman lab, which examines sexual differences in neuroinflammation, the gut microbiome, and behavior in response to a high fat diet. Her undergraduate thesis looked at sexual dimorphisms of microglia on a high fat, high sucrose diet in the hippocampus. She is passionate about bridging the gap between current scientific research and social issues with particular interest in the neurobiology of stress and experience. At Georgetown, she is excited to join the He lab which explores the effects of experience on neuroplasticity. 
In her free time, she enjoys biking, reading, traveling, and exploring the city. 

Paige Brooks

Thesis Research Topic: Development of the neurons in the inner ear.
Mentor: Dr. Thomas Coate
Regents Hall Science Center, 411
Email: pmb85@georgetown.edu
Paige earned her B.A. in Cellular Neuroscience with a minor in Biology from Colgate University in 2016. While there, she worked with Dr. Jason Meyers on a high honors thesis utilizing the zebrafish lateral line to examine the roles of Wnt and FGF signaling in sensory support cell development and regeneration. She was selected to present this research at the 2016 GSA Allied Genetics Conference: Spotlight on Undergraduate Research. Paige is excited to continue her research on the developing nervous system here at Georgetown.
Outside the lab, Paige enjoys reading, ballet, exploring DC and trying new foods.

Sean Carey

Thesis Research Topic: Neurobiology and Developmental Biology
Mentor: Dr. Kathleen Maguire-Zeiss
Regents Hall Science Center, 411
Email: sdc91@georgetown.edu
Sean attended The College of the Holy Cross as an undergraduate where he was on the track and field team and earned a B.A. in Biology, graduating in 2015. After graduation, he worked as a research technician under Dr. Maryrose Sullivan at the Veterans Affairs Boston Healthcare System, West Roxbury Hospital. The lab’s field of study was urology research with a focus on autonomic neurotransmission and smooth muscle physiology. During his time there, the lab investigated the role of caveolae and myosin-Va in mediating neurotransmission in the bladder. Along with this, the group also investigated Parkinson’s disease and it contributes to bladder dysfunction. While at Georgetown Sean hopes to further his understanding of neurobiology and developmental biology.  Sean has joined the lab of Kathy McGuire-Zeiss.

Melissa Collier

Melissa Collier

Thesis Research Topic: Modeling of the spread and distribution of infectious disease.
Mentor: Dr. Shweta Bansal
Regents Hall Science Center,
Email: mac532@georgetown.edu
Melissa earned her B.S. in biochemistry and molecular biology at Florida Southern College, in Lakeland Florida. While there she completed her senior honors thesis on sharpnose shark diet analysis and was a National Oceanic and Atmospheric Administration (NOAA) Holling’s Scholar where she studied the stranding patterns of sea turtles on the Atlantic Coast.  Melissa worked in environmental education for a year before getting her masters in marine mammal science at the University of Miami and completing an internship working with bottlenose dolphin photo-identification at the NOAA Miami Lab. Following her master’s graduation, she worked as a Marine Endangered Species Observer until she joined the Bansal Lab in 2018 to study how the disease spreads in marine mammal and other animal social systems. You can usually find her outdoors, petting dogs, or eating breakfast for every meal.

Mia Cozart

mia cozart

Thesis Research Topic: Neural regeneration and neuron-glia interaction.
Mentor: Dr. Jeffrey Huang
Regents Hall Science Center, 411
Email: mdc143@georgetown.edu
TBA

Dillon Damuth

Thesis Research Topic: Neural induction in Xenopus laevis.
Mentor: Dr. Elena Silva
Regents Hall Science Center, 411A
Email: dld66@georgetown.edu
Dillon joined the PhD program in the Department of Biology in 2013, studying early neural development in Elena Silva’s lab group. He received his BA in Biology in 2013 from Elmira College (NY), where his research involved quantification and identification of controlled substances in solution via GC-MS, with the eventual goal of studying thermal degradation rates of these substances in synthetic urine. (Unfortunately, this goal was not reached.)
Outside of time spent in the lab or doing coursework, Dillon cares for his several geckos and enjoys spending time outside and traveling.

Heriberto DeLeon

Thesis Research Topic: Immune responses to Giardia lamblia.
Mentor: Dr. Steven Singer
Regents Hall Science Center, 201
Email: hd316@georgetown.edu
TBA

Alp Demirhan

Thesis Research Topic: Development of the neurons in the inner ear.
Mentor: Thomas Coate
Regents Hall Science Center, 411
Email: md1857@georgetown.edu

Alp is currently a PhD student at Dr. Coate’s lab. He earned his BS in Audiology from the Baskent University in 2019 and has two MS degrees one from Ege University in Neuroscience and the other from the University of Wyoming in Zoology&Physiology. At Georgetown, he’s been focusing on inner ear neurobiology. In his spare time, Alp enjoys trying new restaurants, spending time with his friends, and traveling.”

Dennis DiMaggio

Dennis

Thesis Research Topic: Gene expression patterns in Staphylococcus aureus
Mentor: Dr. Shaun Brinsmade
Regents Hall Science Center, 311/301A
Email: dad148@georgetown.edu
Originally from Southeast Virginia, Dennis graduated from Old Dominion University in the spring of 2018 earning his B.S. in Biology with a Minor in Music Performance. After completing his degree, he began working in the Biological Sciences Support Facility at ODU. While working there, he developed close connections with the research faculty on campus and eventually transitioned to working as a technician in the Daines lab on the Gram-negative, halophilic pathogen, Vibrio vulnificus, studying the effect of a Type II Toxin-Antitoxin System on growth. His specific interests include microbial pathogenesis, host-pathogen interactions, and the bacterial stress response.
Away from the lab, Dennis enjoys trying new places to eat in DC, spending time with his cat, practicing French horn, cooking, and sipping a nice glass of whiskey at the end of a long day.

Marcelle Ferreira

Marcelle Ferreira

Thesis Research Topic: Gene expression patterns in Staphylococcus aureus
Mentor: Dr. Shaun Brinsmade
Regents Hall Science Center,
Email: mcf126@georgetown.edu
Marcelle got her B.S. in Pharmacy at the Federal University of Espirito Santo, Brazil in 2013, and, subsequently, her M.S. in Microbiology at the Federal University of Rio de Janeiro, Brazil, in 2015. Before coming to the US, she worked as a Pharmacist for 5 years at the Brazilian Army. Now she is a PhD student in the Brinsmade Lab where she is interested in understanding how branched-chain fatty acids, and therefore, membrane composition, regulates virulence in Staphylococcus aureus throughthe Sae RS Two-Component System.

Deborah J. George

Deborah George

Thesis Research Topic: Development of the neurons in the inner ear.
Mentor: Dr. Thomas Coate
Regents Hall Science Center,
Email: djw103@georgetown.edu
Originally from Brookline, MA, Deb graduated from Virginia Polytechnic and State University in 2015 earning her B.S. in Animal and Poultry Sciences with a dual emphasis in livestock and equine science. In 2019, she received her M.A. in Biology from American University, working in computational genomics with Dr. John Bracht. There she performed genomic and transcriptomic studies on the thermophilic worm, Halicephalobus mephisto (“The Devil Worm”), revealing adaptation(s) to its sub-terrestrial environment involving elevated heat. She then worked for two years as a mouse breeder for NIH at Janelia Research Campus. She has now joined the lab of Dr. Thomas Coate, and aims to further understand the molecular mechanisms and guidance cues directing type II SGN turning and OHC innervation.

Mara Heilig

mara heilig

Thesis Research Topic: Mosquito habitat adaptation.
Mentor: Dr. Peter Armbruster
Regents Hall Science Center,
Email: mch284@georgetown.edu

Jingwen Hu

Thesis Research Topic: Neural regeneration and neuron-glia interaction.
Mentor: Dr. Jeffery Huang
Regents Hall Science Center, 401/411A
Email: jh1750@georgetown.edu
Jingwen Hu is a Ph.D. student in Dr. Jeffery Huang’s lab, which is focusing on Multiple Sclerosis (MS). Jingwen has been interested in neuronal degenerative diseases since she was an undergraduate student and focused on studying Alzheimer’s disease. For her Masters Thesis, she conducted research on Parkinson’s disease. After that, she joined New York Stem Cell Foundation to work on the stem cell research in MS. In the Huang laboratory, she is focusing on the mechanism of spontaneous remyelination happening MS.
In her spare time, Jingwen enjoys traveling, painting, sports, and music.

Ellen R. Jacobs

Ellen jacob

Thesis Research Topic: Dolphin behavior.
Mentor: Dr. Janet Mann
Regents Hall Science Center,
Email: erj22@georgetown.edu
Ellen received her Bachelor’s in Ecology, Behavior, and Evolution from the University of California, San Diego in 2016, where she completed an honors thesis on density estimations of Cuvier’s beaked whales using passive acoustic monitoring with the Scripps Institution of Oceanography. After graduating, she worked as a research intern at the Monterey Bay Aquarium Research Institute, the Smithsonian Tropical Research Institute, and Woods Hole Oceanographic Institute. In 2019 she received her Master’s in Zoophysiology from Aarhus University in Aarhus, Denmark, where she did her thesis on the active space of sperm whale social calls. Ellen came to Georgetown to begin her PhD studies in 2019, where she uses a combination of behavioral ecology and bioacoustic techniques to understand the lives of bottlenose dolphins. 
Outside of her academic interests, Ellen enjoys reading, hiking, and traveling.

Grace Jeschke

Grace Jeschke

Thesis Research Topic: Study of large-scale patterns of insects, mostly butterflies.
Mentor: Dr. Leslie Ries
Regents Hall Science Center, 301/311A
Email: grj14@georgetown.edu
She is interested in climate change and butterfly ecology.

Rita Kosile

RITA

Thesis Research Topic: Immune responses to Giardia lamblia.
Mentor: Dr. Steven Singer
Regents Hall Science Center, 201
Email: rta18@georgetown.edu
Rita is a Ph.D. student in the Singer Lab. She received her Bachelor’s degree from the Federal University of Technology, Akure, Nigeria. She got her MS from Auburn University, Alabama where she worked on the Interaction of Chromobacterium species with Chytrid fungus in the Mendonca lab. She is now interested in the dynamics of infections investigating how the microbiome is influenced by Giardia lamblia infections. 
In her spare time, She enjoys cooking various Nigerian dishes and trying out American, Asian and Mexican recipes. 

Katherine M. Kraft

Katherine Kraft

Thesis Research Topic: Cell fusion and the control of meiosis.
Mentor: Dr. Mark Rose
Regents Hall Science Center,
Email: kmk314@georgetown.edu

Emma Lederer

Emma Lederer

Thesis Research Topic: Plant-insect interactions.
Mentor: Dr. Martha Weiss
Regents Hall Science Center,
Email:  ekl71@georgetown.edu

Emma is a second year PhD student in Martha Weiss’ lab studying ecosystem engineering caterpillars. Her research is focused on understanding the cues that guide primary and secondary occupancy in caterpillar-built leaf shelters as well as other aspects of caterpillar behavior and ecology. Emma is a proud member of Georgetown’s Alliance of Graduate Employees (G.A.G.E.) and enjoys her work as a Teaching Assistant. 

Haeli Lomheim

Thesis Research Topic: Neural induction in Xenopus laevis
Mentor: Dr. Elena Silva
Regents Hall Science Center, 411A
Email: hjl63@georgetown.edu
Haeli Lomheim is from Petaluma, CA. She lived in Marin County for the last ten years and got a BS in psychology and a BA in chemistry from Dominican University of California. When Haeli graduated, she did my masters research in Dr. Meredith Protas’ lab in Biology, studying a non model organism called Asellus aquaticus and looked for candidate genes for eye degeneration, pigmentation, and metabolism. Haeli is now working in Dr. Elena Silva’s lab here at Georgetown. She is interested in working in industry in the future.

Shican (Claire) Li

Thesis Research Topic: Attachment mechanism of the intestinal parasite Giardia lamblia
Mentor: Dr. Heidi Elmendorf
Regents Hall Science Center, 311/319A
Email: sl1453@georgetown.edu
Shican (Claire) received her BS degree from University of New Haven and an MS from Brandeis University. She is now working on her Ph.D. degree in the Elmendorf lab studying the attachment mechanism of the intestinal parasite Giardia lamblia. She is particularly interested in investigating how Giardia responds to environmental cues to find its attaching site during infection, and especially, how Giardia interacts with intestinal mucus. She plans to explore these questions using biological and physical approaches.
Besides science, Claire enjoys singing Beijing Opera, writing poetry, and playing Chinese zither occasionally.

Ursula Machi

Ursula machi

Thesis Research Topic: Cell fusion and the control of meiosis.
Mentor: Dr. Mark Rose
Regents Hall Science Center, 311
Email: ujm2@georgetown.edu
Ursula graduated from Pennsylvania State University in 2016 with a major in biotechnology and a minor in microbiology. While there, she worked on crystallography studies of iron-sulfur cluster proteins under Dr. Squire Booker. She then went on to a research associate position at Carnegie Mellon University in the lab of Dr. Tina Lee, where she studied the mechanism of ER tubule fusion. She has now joined the lab of Dr. Mark Rose, and aims to further understand the process by which two cells become one. 
Outside of lab, Ursula enjoys cooking, traveling and watching live music. 

Meredith MacQueeney

meredith macqueeny

Thesis Research Topic: Dolphin behavior.
Mentor: Dr. Janet Mann
Regents Hall Science Center, 561
Email: mem505@georgetown.edu
Meredith earned a B.S. in Marine Science and Environmental Studies from Eckerd College in 2019. As an undergraduate she worked with the Eckerd College Dolphin Project on research aiming to enhance our understanding of the biology of bottlenose dolphins in Tampa Bay, Florida. At Eckerd, she undertook a study characterizing boater interactions with the dolphins which was published in Human Dimensions of Wildlife. In the fall of 2019, she worked as a research assistant for the Shark Bay Dolphin Project (SBDP) in Western Australia where she began research centered around maternal investment. In the spring of 2019, she moved back to Florida for an internship with Mote Marine Laboratory’s Sarasota Dolphin Research Program. Meredith came to the Ph.D. program in Biology at Georgetown in 2021 to continue work with the SBDP. Her research interests include calf development and the role of mothers in maintaining tradition and culture in this wild dolphin population. Meredith hopes that her research will inspire public interest in marine conservation to help ensure that future generations will continue to learn from the fascinating lives of whales and dolphins.
Beyond academics, Meredith enjoys cooking, yoga, live music and the great outdoors! 

Zeeba Manavi

Zeeba

Thesis Research Topic: Neural regeneration and neuron-glia interaction.
Mentor: Dr. Jeffrey Huang
Regents Hall Science Center, 401/411A
Email: zm114@georgetown.edu
Zeeba earned her B.S. in Biology from the University of Maryland. She continued pursuing her passion for science at Georgetown University, successfully completing her M.S. in Biochemistry. During her graduate studies in the laboratory of Dr. Cynthia Rosenthal, she investigated the role
of DNA-binding protein inhibitor (ID3) in transdifferentiation of human fibroblasts to neural stem cells. Her thesis was presented at the University’s Tri-Annual M.S. in Biochemistry and Molecular Biology Poster Presentation, which earned her an Excellence in Internship award. Her interest in cellular reprogramming and neuroregeneration led her to the laboratory of Dr. Richard Schlegel where she focused on studying the signaling pathways involved in Conditionally Reprogrammed Cells (CRCs) propagated in culture media composed of Rho-kinase inhibitor with mouse 3T3 feeder cells. Zeeba is excited to be joining The Huang lab with an interest in studying neural stem/progenitor cell senescence in Multiple Sclerosis.
Outside of the lab, Zeeba enjoys studying Japanese, rock climbing, and making fresh pasta

Juan Carlos  Martinez-Cervantes

Juan Carlos Martinez Cervantes

Thesis Research Topic: Learning and forgetting in Drosophila
Mentor: Dr. Isaac Cervantes-Sandoval
Regents Hall Science Center,
Email: jm3381@georgetown.edu

Molly McEntee

Molly McEntee

Thesis Research Topic: Dolphin behavior.
Mentor: Dr. Janet Mann
Regents Hall Science Center, 561
Email: mhm95@georgetown.edu
Molly received a bachelor’s degree in Biology from Williams College in 2014. As an undergraduate, she spent a summer at the Duke Marine Lab studying the ecology of deep-sea cold-seep ecosystems, and completed an honors thesis on the pollination network of bunchberry dogwood. After graduation, she moved to Kenya as a research assistant for the Mara Hyena Project, where she studied the behavioral ecology of spotted hyenas under Kay Holekamp. Molly then spent a field season in Maine studying the conservation ecology of endangered right whales, before returning to Kenya to study the behavioral ecology of anubis baboons with the Comparative Analysis of Baboon Sociality project under Joan Silk.  Molly joined Janet Mann’s lab as a Ph.D. student in 2017. She is interested in female reproductive behavior in wild bottlenose dolphins.

Bergeline Nguemwo-Tentokam

TBA

 Zachory Park

Zachary Park

Thesis Research Topic: Cell fusion and the control of meiosis.
Mentor: Dr. Mark Rose
Regents Hall Science Center, 311
Email: zmp7@georgetown.edu
Zac graduated from Elmira College in 2017 with a BS in Biology and Biochemistry. At Elmira, he worked in the lab of Daniel Kjar where he studied competitive interactions between ant species. He has always been fascinated by the concept of regulation and the genetic and biochemical regulation of complex biological processes in particular. He joined Mark Rose’s lab group at Georgetown, working on the regulation of meiosis in Saccharomyces cerevisiae.
Outside the lab Zac enjoys reading, trying out local breweries, and exploring D.C.

Joan Reger

Joan Reger

Thesis Research Topic: Neural regeneration and neuron-glia interaction.
Mentors: Dr. Jeffery Huang and Dr. Meng Meng Fu
Regents Hall Science Center, 561
Email: jfr59@georgetown.edu
Joan is a Ph.D. student in Huang’s lab where she studies microtubule dynamics in oligodendrocytes. She earned her B.S. in Biology at Emory University in 2017. While at Emory, she worked in the Wilkinson lab studying yeast prions and also worked with K-12 students in the Atlanta community through the educational outreach program Graduation Generation. Prior to coming to Georgetown, she completed a summer research project on TDP-43 in the Eisenberg lab at UCLA and a public health science internship at the USDA in Washington, D.C.Outside of the lab, Joan enjoys traveling, yoga, DIY projects, and watching The Office.  
Outside of the lab, Joan enjoys traveling, yoga, DIY projects, and watching The Office. 

Tyler Rippel

Tyler

Thesis Research Topic: Community Genetics.
Mentor: Dr. Gina Wimp
Regents Hall Science Center, 501A
Email: tr599@georgetown.edu
In 2011, Tyler earned his BS in Plant Biology with a minor in Environmental Studies from Illinois State University. While there, he did a senior thesis research project on how soil nutrients can influence female frequency in the gynodioecious prairie plant Lobelia spicata. During undergraduate and the first year of graduate school at Villanova University, he was a part of the Men’s Track and Field Team as a 800m runner. At Villanova, Tyler moved towards ecosystem ecology and studied the influence of an invasive grass on microbial communities and nitrogen cycling in temperate forests. He came to Georgetown University to work in Gina Wimp’s lab to investigate how plant-invertebrate interactions can cascade through fungal and microbial communities to influence biogeochemical cycling in coastal salt marshes.
Outside of school he enjoys being in nature, galavanting through D.C., and slapping some bass.

Anais Roussel

Thesis Research Topic: Biosignature detection.
Mentor: Dr. Sarah Johnson
Regents Hall Science Center, 501A
Email: ar1505@as4432
The questions that I am passionate about pertain to biosignatures formation and preservation in the Solar System. I am particularly interested in biosignatures’ preservation processes on Mars, under the destructive effects of Galactic Cosmic Rays. This research will help determine the most plausible locations on the Martian surface where evidence of past life could still be detected by ongoing and future Mars missions. Before starting my PhD at Georgetown, I got a Masters degree in Biotechnologies Engineering (France) and researched biomarkers preservation in Cambrian rocks in Oman as a member of the Summons Lab at MIT.

Pablo Silva Rodríguez

Pablo Silva Rodriguez

Thesis Research Topic: Neural induction in Xenopus laevis
Mentor: Dr. Elena Silva
Regents Hall Science Center, 411A
Email: ps977@georgetown.edu
He came from Guatemala where he obtained a BS in Biology in 2010 and a Licentiate degree in Biology in 2013 at Universidad del Valle de Guatemala. He completed his undergraduate research work with gram-positive pathogens of tomato, specifically Clavibacter michiganensis subsp. michiganensis. In 2012, and obtained an MS in Molecular Medicine at the University of Sheffield, UK. His master’s research project, Transcriptional Regulation of the Neuronal Function in the Developing Zebrafish Central Nervous System, was supervised by Vincent Cunliffe at the MRC Centre for Developmental and Biomedical Genetics. In 2013, he did a short internship at University of Chile, under the supervision of Miguel Concha that aimed to study cilio-genesis and cilio-pathies using zebrafish as an animal model.  He was awarded a Fulbright-LASPAU scholarship to pursue a Ph.D. in Biology at Georgetown beginning in 2015. His research interests include developmental biology, neurobiology, molecular and cellular mechanisms of disease and adaptation, transcriptional regulation and evolutionary biology.  He has joined Elena Silva’s lab group.  
In addition to research, he also loves traveling, loves playing and listening to music and definitively loves coffee (especially with a good conversation). He also enjoys watching NFL games, discovering new tasty beers (big fan of dark beer) and meeting new people and learning about different cultures. 

Prachi Shah

Mentor: Dr. Isaac Cervantes Sandoval
Regents Hall Science Center,
Email: ps1246@georgetown.edu
Prachi earned a B.S. in Biology with minors in education and biological anthropology from Binghamton University in 2021. Her past research was done with Dr. Donald Wilson at the Nathan Kline Institute for Psychiatric Research. She focused on Alzheimer’s disease, specifically investigating the connection between olfaction and genetic markers in mice. She also worked on a project investigating the effects of fetal alcohol syndrome on sleep deprivation. Prachi is excited to continue her research in memory, specifically the process of forgetting here at Georgetown. In her free time, Prachi enjoys reading, knitting/crocheting, and spending time with friends.    

Vaughn Shirey

Shirey Vaughn

Thesis Research Topic: Study of large-scale patterns of insects, mostly butterflies 
Mentor: Dr. Leslie Ries
Regents Hall Science Center,
Email: vms55@georgetown.edu
Vaughn graduated with a B.S. in Environmental Science from Drexel University in 2017. There, Vaughn worked with Dr. Jon Gelhaus on crane fly systematics alongside doing biodiversity informatics work with museum specimens. Following graduation, Vaughn moved to Helsinki, Finland to work as a Fulbright Study/Research Fellow with Dr. Pedro Cardoso at the Finnish Museum of Natural history investigating data bias in biodiversity databases. They worked with Dr. Leslie Ries at Georgetown to understand connections between butterfly metacommunity dynamics and climate change in North American boreal forests.

Henry Stevens

Thesis Research Topic: Migratory Birds and Conservation.
Mentor: Dr. Peter Marra
Regents Hall Science Center,
Email: hcs58@georgetown.edu
Henry graduated from Tufts University (Roll ‘Bos) in 2019 with a joint BS in Biology and Environmental Science. He grew up in Exeter, NH, where he discovered his passion for ornithology. He LOVES birds, and his desire to understand their ecology is what gets him out of bed in the morning (#ForTheBirds). Henry’s research interests lie at the intersection of conservation ornithology and tropical ecology, and his past research has focused on the breeding biology and dispersal of Gray Vireos (Vireo vicinior) in New Mexico, the use of remote audio recorders for surveying cryptic species in the Amazon, improving the conservation site network for migratory shorebirds in the Americas, and uncovering the life histories of Andean Cock-of-the-rocks (Rupicola peruvianus) and other understudied species in the cloud forests of Ecuador. At Georgetown, Henry plans to study the full annual cycle of Neotropical migratory wood-warblers, and use integrated population models to pinpoint factors driving their declines. With over 3.2 billion individual birds lost in North America since 1970, understanding and addressing the threats faced by these species is paramount for mitigating further declines.pecies in the cloud forests of Ecuador. At Georgetown, Henry plans to study the full annual cycle of Neotropical migratory wood-warblers, and use integrated population models to pinpoint factors driving their declines. With over 3.2 billion individual birds lost in North America since 1970, understanding and addressing the threats faced by these species is paramount for mitigating further declines.

Samantha L. Sturiale

Thesis Research Topic: Mosquito habitat adaptation.
Mentor: Dr. Peter Armbruster
Regents Hall Science Center,
Email: sls366@georgetown.edu
Sam is a PhD student working in Dr. Peter Armbruster’s lab. Sam graduated in 2019 from the University of Virginia with a B.S. in biology, specializing in environmental and biological conservation. During her time at UVA, she served as an undergraduate researcher in Dr. David Parichy’s lab studying the genetics of pigment pattern formation in zebrafish. As an undergraduate she also participated in a summer REU program at UVA’s Mountain Lake Biological Station where she investigated self-medication behaviors within the ant seed dispersal mutualism (myrmecochory). She then earned a Master of Science by research in biology at the University of St Andrews in the UK for her thesis work studying the effects of social plasticity within and across generations in a rapidly evolving population of Hawaiian field crickets. At Georgetown, she is interested in exploring how temperature influences survival, energy usage, and development of insects which enter a state of dormancy (diapause) to survive winter. She hopes this work will help us better understand how important temperate insects will respond to projected increases in average winter temperature and frequency of extreme events such as heatwaves. She will explore this topic using an important disease vector, the Asian tiger mosquito (Aedes albopictus).
Outside of lab, Sam enjoys reading, spending time with her pet cat (Kitty), and playing board games with friends.

Muthu Malavika Sugumar

First year student doing rotations through molecular and cellular labs
Regents Hall Science Center,
Email: ms4828@georgetown.edu

Brady Thexton

Brady Thexton

Thesis Research Topic: Plant-insect interactions.
Mentor: Dr. Martha Weiss
Ecology Lab
Email: bt495@georgetown.edu (new window)

Brady is a PhD student working in Dr. Martha Weiss’ lab. Brady graduated from Drew University (Madison, NJ) in 2020 with a B.S. in environmental science and a minor in creative writing. During their time at Drew, Brady worked as a research assistant in Dr. Tammy Windfelder’s lab studying the population dynamics of small mammals in response to white-tailed deer exclusion in regenerating forest habitats and Dr. Alex Bajcz’s lab studying the reproductive ecology of native and non-indigenous Rubus. They also worked part-time to manage non-indigenous plant species in the university’s forest preserve. At Georgetown, Brady’s research focuses on clarifying the relationship between non-indigenous plant species and native insect herbivore communities. As non-indigenous plants continue to spread across the globe with no signs of stopping, it is essential that we understand how the ecological interactions between these groups change over time. Brady is exploring these relationships using species in the grape family (Vitaceae) such as the non-indigenous porcelain berry (Ampelopsis glandulosa) that was brought to D.C. in the 1870s.


Outside of lab, Brady enjoys going for walks with their pandemic puppy, Wendell, and drinking copious amounts of coffee.

Jewel Tomasula

Jewel Lipps Tomasula

Thesis Research Topic: Community Genetics.
Mentor: Dr. Gina Wimp
Regents Hall Science Center,
Email: el785@georgetown.edu
Jewel began her Ph.D. studies at Georgetown in fall 2017, after working for two years at the U.S. Environmental Protection Agency headquarters in DC. Originally from Texas, she went to Southern Methodist University in Dallas, TX for her undergraduate degree. She has field ecology and environmental chemistry experience in several distinct ecosystems, including Appalachian streams, peat bogs, and bottomland hardwood forests. As a student in Gina Wimp’s lab, she investigates how plant-herbivore interactions affect the ecosystem services of Atlantic coast salt marshes. She is passionate about discovering science-based solutions to society’s environmental challenges.

Cesar Velez-Penaloza

Cesar Velez-Penaloza

Thesis Research Topic: Neurogenesis in Xenopus laevis
Mentor: Dr. Elena Silva
Regents Hall Science Center, room # 501A
Email: cdv16@georgetown.edu
Cesar graduated from the University of Maryland-College Park in 2016 with a BS in Animal Sciences and a BA in Spanish.  His plans were to go to Vet school and worked at the campus farm and animal wing at UMD. After graduation, he worked as part of the husbandry staff at NIH. From previous animal work, he decided that vet medicine was not for him. During the completion of his degrees, he took an experimental embryology class which sparked his interested in research specifically in developmental biology. To get more knowledge of current lab techniques he finished a Biotechnology Certificate from Montgomery College.  For his graduate work at Georgetown, he had decided to join Elena Silva’s lab.
Outside of the lab, he tries to be as social as possible to have a balanced life, he loves trying new foods, and learning about different cultures and people.

Nicole Y. Wagner

Thesis Research Topic: Biosignature detection.
Mentor: Dr. Sarah Johnson
Regents Hall Science Center, room # 501A
Email: nyw5@georgetown.edu
Nicole Wagner is a PhD candidate working in Prof. Sarah Stewart Johnson’s lab. Her project focuses mostly on environmental metagenomics. She studies the microbial composition in frozen Antarctic lakes. I also study the degradation and change in microbial communities through time in Antarctica.  
In her free time, she dote on her little poodle, (re)watch episodes of Star Trek, and read corny sci-fi novels.

Maggie M. Weng

Thesis Research Topic: Biosignature detection.
Mentor: Dr. Sarah Johnson
Regents Hall Science Center, room 501A
Email: mw1144@georgetown.edu
Maggie Weng is a PhD student with the Johnson Biosignatures Lab. Maggie graduated from Washington University in St. Louis with a degree in environmental earth science and a minor in writing, and was a member of the Pathfinder program lead by Raymond Arvidson. She completed an REU internship with the Johnson lab during her undergraduate degree, as well as an internship at NASA Goddard Spaceflight Center where she studied the spaceflight compatibility of the MinION portable DNA sequencer. Her research interests include understanding the ecology and community structure of extreme environments, as well as an agnostic understanding of life detection. She loves traveling and fieldwork, and is always interested in looking for intersections of astrobiology work with relevant environmental problems.
When not working in the lab you can find her hiking, knitting, or writing.

Emily Williams

Thesis Research Topic: Migratory Birds and Conservation.
Mentor: Dr. Peter Marra
Regents Hall Science Center,
Email: ejw75@georgetown.edu
Emily is an avian ecologist that has been working with birds for the last ten years. She comes to the Marra lab from working for the National Park Service in Alaska, where she studied the movements, ecology, and behavior of Denali’s resident and migratory birds.  Prior to working at Denali National Park and Preserve, Emily completed her MSc at Kansas State University investigating the patterns and mechanisms to within-season breeding dispersal in grassland sparrows. Emily received her BSc in Wildlife Ecology and Conservation and BA degree in English literature from the University of Florida. Emily’s research interests center in migration ecology, with a particular interest in the evolutionary and ecological processes that give rise to variation in migratory behavior. Emily’s PhD research will focus on understanding the drivers that lead to different migratory strategies between palearctic and Nearctic migratory birds. Beyond her academic interests, Emily is passionate about outreach and the accessibility of science, and never foregoes an opportunity to get people excited about birds.

Former Graduate Students