Hanna H. Gray Fellows Program
The goal of the Hanna H. Gray Fellows Program is to reach, recruit, and retain individuals from the diverse talent pool of early career scientists in the United States. Through their successful careers, HHMI Hanna Gray Fellows will become leaders in academic research who inspire, train, and mentor future generations of scientists.
Since 2017, HHMI has held regular competitions to select Hanna Gray Fellows. In 2021, HHMI expanded our commitment to advance inclusion at key career stages in academic science. The Institute pledged to select up to 25 Hanna Gray Fellows annually for the next decade. Fellows receive funding to support their postdoctoral training and may continue to receive funding during their early career years as independent faculty. Each fellow participates in professional development, mentorship, and networking with their community of peers and the broader HHMI community of scientists across career stages.
In keeping with HHMI’s “people, not projects” philosophy, the Hanna H. Gray Fellows competition is open to those dedicated to basic research from both doctoral and/or medical training paths in the biomedical and life science disciplines, including plant biology, evolutionary biology, biophysics, chemical biology, biomedical engineering, and computational biology. Fellows have freedom to change their research focus and follow their own curiosity for the duration of the award.
About Hanna H. Gray
The Hanna H. Gray Fellows Program honors the contributions of Hanna Holborn Gray, PhD, over her 28 years of service as a trustee of HHMI. A former chair of the trustees, she was one of the eight original trustees appointed in 1984 to govern the Institute. During her tenure, the Institute made significant changes to its process for selecting the scientists in which it invests, opening its doors to an ever-increasing pool of applicants.
Postdoctoral Training Phase
Fellows will receive annual support of a $80,000 salary for the initial year and a $20,000 expense allowance, paid through a non-renewable grant to the training institution. This phase of the award is for a minimum of two and maximum of four years.
Fellows will receive $250,000 in research funding and a $20,000 expense allowance per year, paid through a non-renewable grant to the institution where they have attained a faculty position. This phase of the award has a maximum length of four years.
Conditions of the Award
- Fellows in both postdoctoral training and faculty phases are required to devote at least 75% of their total effort to research.
- To transition to the faculty phase of the program, fellows must obtain a tenure-track (or equivalent) faculty position at a U.S. (including Puerto Rico) research institution with a doctoral-level graduate program in their area of interest.
- Fellows will be expected to attend an HHMI science meeting each year and provide an annual progress report.
Biafra Ahanonu, PhDHHMI Hanna Gray Fellow / 2020–Present University of California, San Francisco
Mentor: Allan Basbaum, PhD
Biafra Ahanonu wants to understand the neural and molecular basis of pain, a complex experience that integrates sensory information with ongoing brain states. Ahanonu is pioneering methods to record spinal cord and brain neuron activity in active, non-anesthetized animals and identify pain-modulating proteins in neurons and synapses that process pain. Ahanonu hopes these findings will help the millions of Americans who suffer from chronic pain.
Jose L. Alejo, PhDHHMI Hanna Gray Fellow / 2018–Present
Mentor: Kate Adamala, PhD
Jose L. Alejo is investigating one of nature’s most important molecular machines, the ribosome. All living cells use ribosomes to translate the genetic code into proteins. Alejo plans to develop techniques for generating synthetic cells that contain different versions of the ribosome and its molecular partners. He seeks to build a platform for engineering new biomaterials from antibiotics to polymers. Alejo’s work could also shed light on the origin of life on Earth and how life might emerge elsewhere in the universe.
James R. Allen, PhDHHMI Hanna Gray Fellow / 2020–Present Massachusetts General Hospital
Mentor: David Langenau, PhD
James Allen is working to understand how pediatric cancers, such as T-cell acute lymphoblastic leukemia, or T-ALL, co-opt our body’s mechanisms for their own ends. A major hurdle to developing a more effective treatment for T-ALL is a limited understanding of the genes and pathways that drive the cancer’s spread and are required for tumor growth. Allen plans to uncover novel drivers of the disease and identify pathways that can be targeted by therapeutics.
Nicolas Altemose, PhD, DPhilHHMI Hanna Gray Fellow / 2020–Present Stanford University Assistant Professor in the Department of Genetics
Nicolas Altemose is developing new technologies that use cutting-edge DNA sequencing machines to map protein-DNA interactions in uncharted regions of the human genome. Across the genome, thousands of proteins must interact with DNA to read, regulate, repair, and replicate it. Altemose hopes mapping those interactions can uncover the molecular foundations of various diseases.
Thiago Monteiro Araújo dos Santos, PhDHHMI Hanna Gray Fellow / 2018–Present Harvard University
Mentor: Daniel Kahne, PhD
Thiago Monteiro Araújo dos Santos finds the invisible world of microbes captivating. By figuring out how bacteria build their outer walls, he hopes to inhibit the process. Such interference may ultimately lead to new ways to stop deadly infections. Santos aims to uncover how some bacteria’s cellular machinery manufactures and installs stabilizing protein “bricks” into cell walls. Weakening these walls could one day form the basis of new antibiotics, a development that could thwart antimicrobial resistance.
Begüm Aydin, PhDHHMI Hanna Gray Fellow / 2022–Present The Rockefeller University
Mentor: Daniel Mucida, PhD
Begüm Aydin wants to understand how the environment affects the nervous system. Focusing on the nervous system inside the gut, often called “the second brain,” she is investigating the effects of gut microbiota and immune cells on the development and maintenance of gut neurons. By pursuing how neurons develop and recover upon microbial insults and inflammation, Aydin hopes to provide insights into neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS) and Parkinson’s disease, where pathological inflammation causes neuronal damage.
Halleh B. Balch, PhDHHMI Hanna Gray Fellow / 2022–Present Stanford University
Mentor: Jennifer Dionne, PhD
Halleh Balch is a physicist pioneering new technologies deployed on autonomous underwater vehicles (AUVs) to study oceanic microorganisms and their impact on climate and human health. By developing methods for use on board AUVs to measure metabolites and the genes that encode for them, Balch aims to link gene expression and metabolic function with environmental drivers like temperature, nutrients, and acidity. Balch hopes this work will uncover new catalysts, useful therapeutics, and pathways to greater climate resilience.
Christopher Barnes, PhDHHMI Hanna Gray Fellow / 2017–Present Stanford University Assistant Professor of Biology
With cutting-edge crystallography and microscopy techniques, Christopher Barnes aims to reveal - in extreme detail - how newly isolated antibodies neutralize HIV-1 by latching onto viral envelope proteins. Barnes also plans to uncover how the virus gains illicit entry into cells by examining the structural changes that help the virus lock into a cellular target. These insights may point out ways to devise even more powerful therapeutics, including rationally designed HIV-1 antibodies, which could help scientists stamp out the shifty virus for good.
Julia Belk, PhDHHMI Hanna Gray Fellow / 2023–Present Stanford University
Mentor: Howard Y. Chang, MD, PhD
Julia Belk studies the swarms of “nano-robots” patrolling our bodies – sometimes known as the immune system – that can cause, prevent, or cure disease. As a doctoral student, Belk focused on reprogramming immune cells to fight cancer more effectively. Now, she is investigating whether these cells can be engineered to protect the aging brain. These studies could inform immunotherapeutic approaches to mitigate or pre-empt neurodegenerative diseases, including Alzheimer’s disease.
Neville P. Bethel, PhDHHMI Hanna Gray Fellow / 2019–Present University of Washington
Mentor: David Baker, PhD
Some proteins form gels, some provide molecular transportation, and still others, such as spider silk, are stronger than steel by weight. Neville Bethel wants to understand how microscopic molecules combine to take on such diverse roles. After creating a collection of protein fibers from scratch, Bethel will test them to learn which molecular interactions give rise to which mechanical properties. Then, he’ll create a computational model that can predict those properties from a protein’s structural code.
Steve L. Bonilla, PhDHHMI Hanna Gray Fellow / 2020–Present University of Colorado Anschutz Medical Campus
Mentor: Jeffrey Kieft, PhD
Steve Bonilla is using cryogenic electron microscopy, known as cryo-EM, to visualize diverse, dynamic, functional RNA structures. A major goal of biomedical research is to be able to predict how strands of functional RNA – strands that do not code for proteins – will fold into three-dimensional structures, but it is often difficult to visualize those structures due to their small size and dynamic, fluctuating nature. Cryo-EM may now allow researchers to do this. Bonilla plans to use his training in chemical engineering and computer science to help develop a system to predict RNA structure and function.
Alain Bonny, PhDHHMI Hanna Gray Fellow / 2022–Present The Rockefeller University
Mentor: Elaine Fuchs, PhD
Alain Bonny is working toward understanding how diverse cell types within a tissue coordinate actions to carry out complex behaviors. This process is especially critical when the tissue undergoes an injury, where the inflammatory response must be coordinated with tissue repair in a timely manner. Bonny is adapting and developing new tools to probe how cells communicate and coordinate the transition between inflammation and tissue repair. Understanding this “molecular handoff” will shed light on conditions that emerge when these precise coordination mechanisms break down.
Ali Sina Booeshaghi, PhDHHMI Hanna Gray Fellow / 2023–Present University of California, Berkeley
Mentor: Aaron Streets, PhD
Our DNA consists of a static set of base pairs that are dynamically influenced by lifestyle and environmental factors. These influences vary across populations and may confer differential risk for disease susceptibility. Sina Booeshaghi studies this variation within the historically overlooked non-protein-coding region of our genome. He works with chromatin accessibility and gene expression data in mouse models of obesity, cancer, and diabetes, aiming to produce robust genomics measurements that associate genomic variation with disease.
Anna Bowen, PhDHHMI Hanna Gray Fellow / 2022–Present University of Washington
Mentor: Nicholas A. Steinmetz, PhD
Choices are shaped by more than just the outside world. Anna Bowen endeavors to understand how the brain uses signals from the body to add meaning to external information and build adaptive behaviors. Using widescale neural recordings and simultaneous physiological measurements, Bowen is mapping the neural networks and signaling underlying food value learning. She hopes her work will reveal how we learn to predict food’s effect on the body and guide development of therapies for metabolic disease.
María Angélica Bravo Núñez, PhDHHMI Hanna Gray Fellow / 2020–Present Harvard University
Mentor: Andrew Murray, PhD
María Angélica Bravo Núñez wants to understand the evolutionary role of aneuploidy, a state where cells have extra or too few chromosomes, which contributes to both cancer progression and drug resistance in fungal pathogens. Aneuploidy occurs when errors happen during the division of a cell’s nucleus. Bravo Núñez is investigating whether genes that play a role in creating sperm and egg cells, if turned on under the wrong conditions, can create aneuploid cells, and whether these cells may offer genetic advantages by increasing resistance to stressors.
John Brooks, PhDHHMI Hanna Gray Fellow / 2017–Present Princeton University Assistant Professor in the Department of Molecular Biology
John Brooks is investigating how mammals’ internal clocks affect microbes that live in the gut. The mix of microbial species in these communities oscillates throughout the day. Scientists have linked these swings to the circadian clock, the biochemical timekeeper that governs everything from appetite to sleep. Brooks plans to unravel how the circadian clock works with the innate immune system to regulate microbe metabolism. His results could expose how the clock/microbiota interplay shapes the health of the host.
Giancarlo Bruni, PhDHHMI Hanna Gray Fellow / 2022–Present University of California, Los Angeles
Mentor: Leonid Kruglyak, PhD
Biological cells – from bacteria to those in our bodies – maintain a difference in voltage, called membrane potential, between their exterior and interior. Membrane potential can power molecular machines and transmit cellular signals. Giancarlo Bruni seeks to understand how evolution has shaped membrane potential within and across species, and how differences in membrane potential contribute to biological variation between individuals. This work will provide insights into the role played by membrane potential in health and disease.
Elsy Buitrago-Delgado, PhDHHMI Hanna Gray Fellow / 2019–Present California Institute of Technology
Mentor: Long Cai, PhD
Elsy Buitrago-Delgado knows the importance of location in a spatial context. She wants to use new imaging technology to map the spatial distribution of thousands of RNA molecules in mouse embryos during their first few days of development. These molecules contain instructions for making proteins, which, in turn, guide cellular behavior. Buitrago-Delgado hopes to show how RNA quantity and spatial distribution – within and between cells – helps shape the magnificent choreography of embryonic development.
Jasmin Camacho, PhDHHMI Hanna Gray Fellow / 2022–Present Stowers Institute for Medical Research
Mentor: Nicolas Rohner, PhD
Bats are an extremely diverse and successful group of mammals. A trait that has evolved multiple times in bats is preference for a sugary nectar diet. Jasmin Camacho is studying wild bats using cutting-edge metabolomics to identify and map the metabolic mechanisms that protect against the damaging effects of sugar consumption. Camacho’s goal is to uncover the nectar adaptations that underlie how mammals thrive on increased sugar consumption, which could help efforts to fight metabolic diseases like diabetes.
Kyle Card, PhDHHMI Hanna Gray Fellow / 2020–Present Cleveland Clinic Foundation
Mentor: Jacob Scott, MD, DPhil
So long as humans use antibiotics to fight bacteria, antibiotic resistance will be with us. Kyle Card is using bacteria from various stages of the seminal E. coli long-term evolution experiment (LTEE) – which has tracked bacterial evolution over more than 70,000 generations – to examine how bacteria’s evolutionary history, together with population size and mutation rates, contribute to the evolution of antibiotic resistance and associated fitness costs.
Ava Carter, PhDHHMI Hanna Gray Fellow / 2020–Present Harvard Medical School
Mentor: Michael Greenberg, PhD
Ava Carter is working to understand how interpretation of sensory cues drives human brain development throughout childhood. Carter is studying a family of proteins called zinc finger transcription factors that are enriched during this process. By looking at the targets of these factors, Carter hopes to uncover how a relatively unexplored part of the genome might contribute to human brain development and evolution.
Lynne Chantranupong, PhDHHMI Hanna Gray Fellow / 2017–Present Harvard Medical School
Mentor: Bernardo Sabatini, MD, PhD
Lynne Chantranupong knows how to get cells to spill their secrets. She has characterized key regulators of a signaling pathway that tells cells to grow, a process that goes awry in cancer and diabetes. Now, she is setting her sights on the brain. Chantranupong plans to isolate intracellular packets that contain neurotransmitters, signaling molecules that carry messages between nerve cells. She wants to probe the contents of these packets using mass spectrometry. This high-resolution method promises to reveal a complex and dynamic atlas of neurotransmitters in the brain.
Yiyin Erin Chen, MD, PhDHHMI Hanna Gray Fellow / 2018–Present Broad Institute of MIT and Harvard Assistant Professor, MIT Biology and Core Institute Member, Broad Institute
Yiyin Erin Chen doesn’t believe in “good” or “bad” microbes; she considers the context. Chen, a dermatologist and scientist, explores the interplay between our immune system and the microbes that inhabit our skin. Her focus is how a microbe’s context – its genetic makeup and the roster of microbes nearby – influences its potential for maintaining health or causing inflammation. By decoding the mechanisms that govern these interactions, Chen’s work could lead to engineered microbes as a new way to treat skin diseases such as eczema.
Cagney Coomer, PhDHHMI Hanna Gray Fellow / 2022–Present Dartmouth College
Mentor: Marnie E. Halpern, PhD
Neural circuits are the fundamental connections underlying all brain functions, from cognition to behavior. Understanding these complex pathways has important implications for neuroscience research and human neurological disorders. Cagney Coomer is generating transgenic tools – which change an organism’s DNA – for transsynaptic tracing in zebrafish to map, monitor, and manipulate neural circuits. She aims to apply these powerful techniques to study both the developing and regenerating nervous system.
Kevin Cox Jr., PhDHHMI Hanna Gray Fellow / 2019–Present Donald Danforth Plant Science Center
Mentor: Blake Meyers, PhD
Kevin Cox Jr. is seeking a cellular-level view of the battles between plants and microbes. He’s analyzing gene activity cell by cell to better understand how plants resist or succumb to microbial invaders. Pinpointing where in the plant specific genes are active can help him determine how plant cells and microbes communicate. Cox hopes that decoding those cellular signals will lead to novel ways of improving crop yields, and ultimately to feeding more people.
Willow Coyote-Maestas, PhDHHMI Hanna Gray Fellow / 2020–Present University of California, San Francisco Assistant Professor in the Department of Bioengineering and Therapeutic Sciences
TrpV1 is the protein that sends signals of searing pain after a bite of a spicy chili pepper – but it also responds to scalding heat. Willow Coyote-Maestas is detailing the mechanisms by which this protein senses heat. Coyote-Maestas looks for genetic mutations that change TrpV1’s response to high temperatures, then uses high-resolution microscopes to examine how changes in temperature sensation alter protein structure. Linking TrpV1’s shape to its temperature sensitivity will help scientists better understand how we feel heat.
Andrea Cuentas-Condori, PhDHHMI Hanna Gray Fellow / 2022–Present Yale University
Mentor: Daniel Alfonso Colón-Ramos, PhD
Andrea Cuentas-Condori’s research aims to understand how some neurons communicate using two different neurotransmitters rather than one. Dual-transmission is a conserved capacity of neuronal circuits that scientists are just starting to understand at the cellular and circuit levels. Cuentas-Condori will use the compact nervous system of C. elegans to identify strategies that neurons use to organize different populations of synaptic vesicles along a single axon and how dual-transmitter signals integrate to modulate the behavior of a living animal.
Katherine Deets, PhDHHMI Hanna Gray Fellow / 2023–Present University of Utah
Mentor: Nels Elde, PhD
Aquatic environments contain a wealth of hidden host-pathogen interactions that can teach us about the evolution of eukaryotic immunity. To uncover some of these interactions, Katherine Deets is studying antiviral responses in ciliates – single-celled eukaryotes that play an important role in moving nutrients throughout aquatic ecosystems. She is also developing a new model system to determine how these ciliates might concentrate and transmit viruses or other pathological microbes between fish.
Emily Dennis, PhDHHMI Hanna Gray Fellow / 2019–Present Janelia Research Campus Janelia Group Leader
Our understanding of biology and disease depends on model organisms such as rats, mice, and flies. Emily Dennis is investigating important differences between species commonly used in research. She’s studying rats and mice to learn how their brains can solve similar problems and produce comparable behaviors. Dennis’s work will help scientists better translate findings across species. Long-term, her research could improve the study of human diseases, such as Alzheimer’s, in animal models.
Marty Douglass, PhDHHMI Hanna Gray Fellow / 2023–Present Vanderbilt University
Mentor: Eric Skaar, PhD, MPH
Martin Douglass is interested in studying Clostridioides difficile, the leading cause of hospital-acquired intestinal infections. To establish infection, the bacterial pathogen must outcompete a host’s gut microbiota and immune system for limited nutrients. Understanding how C. difficile scavenges essential nutrients will lay the foundation to develop alternative strategies to treat this urgent public health threat.
Kelsie Eichel, PhDHHMI Hanna Gray Fellow / 2019–Present Stanford University
Mentor: Kang Shen, PhD
Neurons face a traffic control challenge. They’re constantly sending different sets of proteins to different parts of the cell – and delivery mix-ups can be disastrous. Kelsie Eichel is studying how neurons sort and dispatch proteins, and what happens when deliveries get lost along the way. A better grasp of the basics could help scientists understand why such mishaps are common in neurodegenerative diseases like Alzheimer’s and Parkinson’s.
Kiara Eldred, PhDHHMI Hanna Gray Fellow / 2022–Present University of Washington
Mentor: Thomas A. Reh, PhD
Kiara Eldred wants to know how neuronal cell fates are specified during retinal development. Using retinal organoids – retinal tissue cultures derived from human stem cells – as a model system, Eldred seeks to understand the factors that help generate important cell types in the retina, as well as the factors that divert cells down an unplanned path toward tumorigenesis. Eldred believes that a better understanding of retinal development will allow her to regenerate retinal tissues lost in blinding diseases and understand the tipping points that drive tumorigenesis.
Carolyn Elya, PhDHHMI Hanna Gray Fellow / 2018–Present Harvard University
Mentor: Benjamin de Bivort, PhD
Carolyn Elya is studying how microbes hijack insect nervous systems. Insects with certain parasitic fungal infections end their lives like zombies, somehow compelled to climb to a high point before spores explode from their bodies. Elya discovered and developed a model system for laboratory studies of this phenomenon using a fungus that infects fruit flies. Her neural and molecular probing of parasitic mind-control is advancing understanding of how animal brains produce behavior, with potential long-term applications for mental health treatment.
Kow Akaa Essuman, MD, PhDHHMI Hanna Gray Fellow / 2023–Present Massachusetts General Hospital
Mentor: Christopher A. Walsh, MD, PhD
Mutations accumulate in both normal and diseased tissues with age and are thought to drive increasing risk of cancer. Kow Essuman is interested in better understanding how mutations accumulate in the human brain, and how mutations drive brain tumor growth. Using single cell sequencing technologies on brain tissues from normal individuals and from individuals with the brain tumor predisposition syndrome NF1, Essuman hopes to uncover genetic drivers and therapeutic targets for brain cancer.
Chantell Evans, PhDHHMI Hanna Gray Fellow / 2017–Present Duke University Assistant Professor of Cell Biology
Mitochondria provide the energy needed for nerve cells to function, but when aged or damaged, these organelles can potentially be harmful to the cell. Chantell Evans will explore the multiple ways neurons sequester and eliminate damaged mitochondria. This cleanup process, called mitophagy, can malfunction in people with Alzheimer’s, Parkinson’s, and other neurodegenerative diseases. By studying healthy nerve cells and cells from people with neurodegenerative diseases, Evans plans to find out how nerve cells perform this important quality control, and how the process might be corrected when something goes wrong.
D’Juan Farmer, PhDHHMI Hanna Gray Fellow / 2018–Present University of California, Los Angeles Assistant Professor in the Department of Molecular, Cell and Developmental Biology
D’Juan Farmer hopes to establish the origins of vertebrate birth defects. His interest in how organs develop prompted a focus on stem cells – namely, their life span and maintenance. Farmer thinks birth defects like craniosynostosis, when the bones of a baby’s skull fuse prematurely, might result from an inability to maintain stem cells in the long-term. By studying craniosynostosis in zebrafish, he plans to uncover if and how stem cell depletion and dysfunction cause disease.
Yvette Fisher, PhDHHMI Hanna Gray Fellow / 2017–Present University of California, Berkeley Assistant Professor, Molecular & Cell Biology Department & Helen Wills Neuroscience Institute
Yvette Fisher is investigating how nerve cells in the brain perform the myriad computations that underlie perception and behavior. She is particularly interested in the role of voltage-gated ion channels, which regulate the flow of ions in and out of a cell. Fisher is exploring the dynamic interactions between these channels in the fruit fly, by examining their activity in cells that may help the fly navigate using visual cues.
Raul Arturo Ramos-Garcia, PhDHHMI Hanna Gray Fellow / 2023–Present University of California, Berkeley
Mentor: Ellen Lumpkin, PhD
Raul Ramos is investigating the neural mechanisms that underlie distortions of touch perception, including persistent alterations seen in sensory processing disorder (SPD) and reversible distortions induced by psychedelics. His research will use a combination of genetics, electrophysiology, imaging, and behavioral tests to define the effects of psychedelics on touch neuron signaling and tactile behaviors. The work will provide new insights into the cause of SPD and the potential therapeutic benefits of psychedelics.
Alexis Gibson, PhDHHMI Hanna Gray Fellow / 2023–Present Oregon Health & Science University
Mentor: Isabella Rauch, PhD
Alexis Gibson is studying how the epithelial cells that line our intestines play a central role in defense against infections and chronic conditions like inflammatory bowel disease. Using organoids – effectively, miniature intestines derived from biopsies taken from human patients or mice – she wants to examine how cell death is coordinated to maintain the epithelial barrier through the process of extrusion. Studying extrusion will help us to understand and manipulate key differences between homeostasis and inflammation.
Morgan Gilman, PhDHHMI Hanna Gray Fellow / 2020–Present Harvard Medical School
Mentor: Andrew Kruse, PhD
Morgan Gilman is scrutinizing a set of molecular mechanisms that nearly all bacteria use to build their cell walls – in order to help break them down. Several antibiotics, like penicillin, work by blocking the synthesis of peptidoglycan – a key component of bacterial cell walls – at specific stages of its assembly. However, many bacteria have developed resistance to these antibiotics. Gilman hopes to lay the groundwork for new antibiotics that target a family of proteins called the SEDS, which were recently discovered to play a critical role in a different stage of peptidoglycan synthesis.
Daniel Gonzales, PhDHHMI Hanna Gray Fellow / 2019–Present Purdue University
Mentor: Krishna Jayant, PhD
Daniel Gonzales aims to eavesdrop on the chatter between brain cells. Information flows through the brain via vast networks of nerve cells. Figuring out how signals propagate through these networks is key to understanding how animals sense and respond to the world around them. Gonzales plans to develop an array of nano-sized sensors to record the activity of nerve cell networks at the surface of a mouse’s brain.
Leah Guthrie, PhDHHMI Hanna Gray Fellow / 2020–Present Stanford University
Mentor: Justin Sonnenburg, PhD
Leah Guthrie is mapping how gut microbes metabolize certain acids found in foods such as apples, pears, and artichokes. While these acids, known as hydroxycinnamic acids, are common in food, they accumulate at high levels in people with failing kidneys. By studying the byproducts produced when the acids are metabolized, Guthrie hopes to better understand their impact on the gut microbiome and their relationship to kidney disease.
Lauren Hagler, PhDHHMI Hanna Gray Fellow / 2022–Present Stanford University
Mentor: Dan Herschlag, PhD
RNA regulates gene expression by folding into complex structures and binding proteins. Lauren Hagler wants to predict how the structure of RNA inside a cell will affect downstream gene expression for any RNA sequence or mutation. Hagler’s research will bridge the gap between traditional biochemistry and high-throughput genomics to build a predictive model based on biophysical data. She hopes that this model will ultimately allow researchers to predict and modulate gene expression for therapeutic intervention.
Arif Hamid, PhDHHMI Hanna Gray Fellow / 2017–Present University of Minnesota Assistant Professor of Neuroscience
Arif Hamid wants to understand how the brain uses a chemical messenger called dopamine to guide behavior. Using a microscopy technique that offers a window into living brain tissue, he will probe dopamine’s actions in different groups of neurons, such as those that signal directly to blood vessels that supply the brain. Hamid’s studies of the interactions between dopamine-producing neurons and blood vessels could deepen our understanding of how blood hormones influence decision-making and goal-directed behavior.
Michelle Hays, PhDHHMI Hanna Gray Fellow / 2022–Present Stanford University
Mentor: Gavin Sherlock, PhD
Parasites and their hosts shape one another’s evolution. In addition, the environment in which host-parasite conflicts take place can impact who wins and how. Michelle Hays is interested in how hosts evolve to fight back against parasites and the trade-offs associated with self-defense. Through experimental evolution of “killer yeast,” Hays is exploring how yeast’s natural parasites shape its evolution and give rise to biological novelty, while limiting host paths to adaptation.
Emily Heckman, PhDHHMI Hanna Gray Fellow / 2023–Present University of Michigan
Mentor: E. Josephine Clowney, PhD
How are brains built for learning? By studying the brains of diverse insect species with a range of learning abilities, Emily Heckman aims to uncover the building blocks for learning and how their organization has been shaped by evolution. Through identifying brain circuit adaptations, she hopes to define how circuit structure influences the learning process and to test whether certain evolutionary innovations are sufficient to improve learning performances.
Autumn Holmes, PhDHHMI Hanna Gray Fellow / 2020–Present Washington University School of Medicine in St. Louis
Mentor: Michael S. Diamond, MD, PhD
Autumn Holmes is examining how chikungunya virus, which causes debilitating, often chronic arthritis in humans, enters cells and begins the infection process in mice. Like dengue and Zika viruses, chikungunya is transmitted through a mosquito species that, due to climate change and other factors, will likely be found in more parts of the world over the next several decades. Holmes hopes to understand how certain infected cells affect the progression of chikungunya disease and how the virus operates in the early stages of infection.
Christina Homer, MD, PhDHHMI Hanna Gray Fellow / 2023–Present University of California, San Francisco
Mentor: Anita Sil, MD, PhD
Challenging fungal infections, including Valley Fever, are on the rise. Valley Fever is caused by the fungus Coccidioides, which forms a unique and mysterious structure during infection – the spherule. Christina Homer is a physician-scientist who discovered that a family of Coccidioides protease enzymes is required to make spherules. She aims to unlock the role of these proteases in spherule formation and infection, and ultimately develop a protease inhibitor to treat Valley Fever.
Ryan E. Hulett, PhDHHMI Hanna Gray Fellow / 2023–Present Carnegie Science
Mentor: Phillip A. Cleves, PhD
Climate change, perhaps the greatest challenge of our lifetime, is having an impact on animal-microbial interactions, a fundamental feature of animal biology. Ryan Hulett is using symbiotic marine invertebrates, like anemones and corals that take up algae into their own cells, to understand how intracellular microbes reprogram host cell fate decisions during heat stress. This work will illuminate fundamental cellular and molecular mechanisms underlying animal resilience in response to global warming.
Adrian Jinich, PhDHHMI Hanna Gray Fellow / 2019–Present Weill Cornell Medicine
Mentor: Kyu Rhee, PhD
Adrian Jinich wants to wipe out Mycobacterium tuberculosis. Worldwide, these bacteria are the leading cause of death from infectious disease, as they are often resistant to existing treatments. Better drugs require new targets, such as enzymes crucial to the bacteria’s survival that aren’t found in humans. Using the genetic tool CRISPR to turn down the activity of specific genes and see what changes occur, Jinich hopes to identify and characterize hundreds of unknown enzymes, revealing new drug targets.
Aaron Joiner, PhDHHMI Hanna Gray Fellow / 2022–Present University of California, Berkeley
Mentor: James H. Hurley, PhD
Aaron Joiner is a firm believer that structure dictates function: from items that we can easily see and use (e.g., vehicles, furniture, tools) to cellular components that are challenging to visualize (e.g., DNA, RNA, proteins). In his research, Joiner determines the structures of proteins at the atomic scale, using cryogenic electron microscopy (cryo-EM). These structures then serve as the foundation for understanding the proteins’ cellular functions. He is particularly interested in a set of challenging proteins that dynamically interact with organelle membranes and is currently focused on the role of the C9orf72 protein in neurodegenerative disease.
Kalli Kappel, PhDHHMI Hanna Gray Fellow / 2020–Present Broad Institute of MIT and Harvard
Mentors: Aviv Regev, PhD, and Feng Zhang, PhD
Mutations to RNA sequences are responsible for dozens of human diseases. Kalli Kappel is investigating what makes these RNA sequences so toxic by examining the mechanism dictating where they reside in a cell, and how that relates to cellular function. Kappel hopes this work will inform future efforts to develop therapeutics for degenerative diseases.
Maia Kinnebrew, PhDHHMI Hanna Gray Fellow / 2023–Present Stanford University
Mentor: Rajat Rohatgi, MD, PhD
Primary cilia are solitary cell-surface organelles that act as “cellular antennas.” By sensing the extracellular environment, they play critical roles in human metabolic homeostasis. Maia Kinnebrew is a biochemist investigating how the lipid composition and organization of the ciliary membrane regulates its sensory and signaling functions. This work will reveal new principles of membrane biology and uncover strategies to correct human developmental and metabolic diseases.
Maiko Kitaoka, PhDHHMI Hanna Gray Fellow / 2023–Present Whitehead Institute for Biomedical Research
Mentor: Yukiko Yamashita, PhD
Genome quality is paramount for our cells, especially for those that pass genetic information to the next generation. Yet, sperm genomes face unique and long-lasting challenges to their DNA integrity as they mature. Maiko Kitaoka seeks to uncover how these vulnerable sperm genomes are safeguarded and filtered to ensure sperm quality and fertility. Her research will shed light on the intersections between DNA damage responses, genome architecture, and sperm developmental dynamics as she untangles crucial quality control mechanisms that guard genomes across generations.
Linnea M. Lemma, PhDHHMI Hanna Gray Fellow / 2023–Present Princeton University
Mentor: Ned Wingreen, PhD
Cells harness internal activity to organize their components and perform incredible feats, such as plants turning CO2 into sugar. To understand activity-driven phase transitions in living cells, Linnea Lemma studies the pyrenoid, a membrane-less organelle in photosynthetic algae. This organelle concentrates CO2 to enhance photosynthesis. Combining concepts from active matter physics and tools from molecular biology, she is uncovering physical principles for pyrenoid formation and function. These insights will advance our understanding of how cells use energy to bring about organization and life.
Victor Lopez, PhDHHMI Hanna Gray Fellow / 2022–Present The University of Texas Southwestern Medical Center
Mentors: Vincent S. Tagliabracci, PhD, and Joshua T. Mendell, MD, PhD
The advent of sequencing technologies has revealed a remarkable diversity among the protein families of most known species, yet many of these proteins remain uncharacterized. Victor Lopez is combining bioinformatics and biochemistry to identify and characterize new members of one of these families called the ATP-Grasp proteins. These proteins are responsible for many essential biological reactions and Lopez hopes that characterizing their biochemical function will help scientists understand their role in health and disease.
Caitlin Mallory, PhDHHMI Hanna Gray Fellow / 2019–Present University of California, Berkeley
Mentor: David Foster, PhD
Caitlin Mallory studies the brain systems that control navigation. She investigates specialized cells that help rats map their surroundings and recall that map later. Mallory already knows how to read patterns of brain activity to predict where the critter might be heading next. Now she wants to figure out how brain regions important for navigation work together to create those signals – a wiring diagram of the animal’s internal GPS.
David Martinez, PhDHHMI Hanna Gray Fellow / 2020–Present Yale School of Medicine Assistant Professor of Immunobiology
David Martinez is examining the quirks of the human immune system that make our antibody responses to dengue virus infection so different from the defenses mounted against its cousins, which include Zika virus, yellow fever virus, and West Nile virus. When people infected with dengue virus later become infected with a second variant of the virus, they can experience severe, sometimes hemorrhagic reactions. Martinez ultimately wants to understand how the immune mechanisms causing these reactions can be exploited to prevent or cure viral disease.
Lisandro Maya Ramos, MD, PhDHHMI Hanna Gray Fellow / 2023–Present The University of Texas Southwestern Medical Center
Mentor: Joseph A. Hill, MD, PhD
Lisandro Maya Ramos is investigating how adipose-tissue-derived signals affect cardiovascular pathophysiology. Maya Ramos, a scientist and cardiology fellow, plans to unravel how endotrophin, a peptide originating in adipose tissue, drives heart failure with preserved ejection fraction, a type of heart failure associated with ventricular stiffness. His results could unravel novel mechanisms underlying adipose tissue signaling to the heart as well as potential new therapies for heart failure.
Johnathan Maza, PhDHHMI Hanna Gray Fellow / 2022–Present University of California, San Francisco
Mentor: Jim Wells, PhD
Within our cells, proteins are routinely modified by post-translational modifications that grow the diversity and function of the approximately 20,000 proteins encoded by the human genome. Johnathan Maza is interested in developing new chemical biology tools to study poorly understood protein post-translational modifications. Maza hopes studying these modifications can shed new light on their role in biology and disease.
Saria A. McKeithen-Mead, PhDHHMI Hanna Gray Fellow / 2023–Present Stanford University
Mentor: Kerwyn Casey Huang, PhD
Perturbations such as inflammation and antibiotics often lead to disruption of the gut microbiome, with profound impacts on human health. Underlying gut bacterial interactions is the movement of discrete DNA fragments between species, which facilitates their adaptation to the environment. Saria McKeithen-Mead seeks to develop methods for measuring and disentangling molecular mechanisms driving horizontal gene transfer within the human gut. This work will accelerate our understanding of how bacterial adaptation and evolution influence health outcomes.
Melanie McReynolds, PhDHHMI Hanna Gray Fellow / 2018–Present Pennsylvania State University Assistant Professor of Biochemistry and Molecular Biology
Every living cell relies on the molecule NAD+ to keep itself running. Low levels of NAD+ have been linked to both aging and a wide range of diseases, including type-2 diabetes, Alzheimer’s, and cancer. Using sophisticated tools that can track the molecule’s metabolic origin and fate, Melanie McReynolds aims to figure out how NAD+ is produced and used up. Uncovering what governs NAD+ metabolic flux inside cells may clarify – and eventually counter – diseases and aging.
Christopher Medina, PhDHHMI Hanna Gray Fellow / 2022–Present Emory University
Mentor: Rafi Ahmed, PhD
Leveraging our immune system to fight tumors is becoming a frontline therapy for cancer treatments. Yet, in the battle against cancer, our immune cells can become exhausted and lose their tumor-killing potential. Christopher Medina’s research focuses on understanding the mechanisms of immune cell dysfunction at both a metabolic and protein level to help override this brake and reinvigorate the immune response.
Edgar Medina, PhDHHMI Hanna Gray Fellow / 2020–Present University of Massachusetts Amherst
Mentor: Lillian Fritz-Laylin, PhD
Edgar Medina studies chytrids, one of the most ancient lineages of fungi, to explore the evolutionary pressures and adaptations that spurred the divergence of fungi and animals. Chytrids are unique among fungi because they share certain traits with animals that have been lost in other fungi over time, including cells that swim in a similar fashion to animal sperm cells. Medina hopes to uncover the molecular mechanisms underlying these traits in chytrids, which could aid efforts to fight fungal pathogens.
Shan Meltzer, PhDHHMI Hanna Gray Fellow / 2018–Present Harvard Medical School
Mentor: David Ginty, PhD
Though the sense of touch is vital in daily life, it’s still a mystery how the nerve circuitry underlying this sense develops. Shan Meltzer is revealing how sensory neurons form the exquisite structures and connections that govern these cells’ functions. Using new genetic tools, she plans to find and manipulate the molecules that control touch sensory neuron development in mice. Her research could lead to new therapies for restoring touch in people with nervous system disorders or injuries.
Monique Mendes, PhDHHMI Hanna Gray Fellow / 2022–Present Stanford University
Mentor: Carla J. Shatz, PhD
Monique Mendes is working to understand how astrocytes – specialized cells of the central nervous system – coordinate and respond to neuronal activity across brain states and behavior. Mendes wants to use novel imaging technology to simultaneously study the activity of neuronal populations and astrocytes in awake behaving mice. Identifying the mechanism that drives these interactions will answer fundamental questions about astrocyte physiology and the causal influence of astrocyte activity on neural circuits.
Tessa Montague, PhDHHMI Hanna Gray Fellow / 2019–Present Columbia University
Mentor: Richard Axel, MD
Like octopus and squid, cuttlefish have an amazing ability to change color to camouflage themselves. Tessa Montague is investigating how these chameleons of the sea turn the background colors and patterns their eyes perceive into a matching display on their own skin. By tracing how a cuttlefish’s nerve cells translate visual information into instructions for color-changing structures in their skin, she plans to explore how the brain creates internal images of the outside world.
Gabriel Muhire Gihana, PhDHHMI Hanna Gray Fellow / 2022–Present The University of Texas Southwestern Medical Center
Mentor: Gaudenz Danuser, PhD
Gabriel Muhire Gihana studies the role of cell morphology in regulating the molecular signaling of RAS, a prevalent human oncogene. Gihana seeks to understand how RAS-induced cell morphological changes contribute to the potential of RAS to cause cancer. Because direct inhibition of oncogenic RAS has proven very difficult, studying other cellular parameters that promote RAS cancer will likely lead to novel therapies.
Evert Njomen, PhDHHMI Hanna Gray Fellow / 2020–Present Scripps Research
Mentor: Benjamin F. Cravatt, PhD
Evert Njomen is using small molecule compounds known as chemical probes to identify specific proteins that could be used to develop treatments against a wide range of bacteria and viruses. The proteins Njomen studies are involved in recycling cellular waste and debris, a process known as autophagy, which also plays a central role in the immune system’s control of pathogens. Njomen hopes to develop advanced probes that can be used to ramp the autophagy process up or down for potential use in pharmaceuticals to target pathogens, including drug-resistant strains of bacteria.
James Nuñez, PhDHHMI Hanna Gray Fellow / 2017–Present University of California, Berkeley Assistant Professor of Biochemistry, Biophysics and Structural Biology
James Nuñez is developing new tools to allow researchers to manipulate the activity of multiple genes simultaneously. The CRISPR-based technology will help scientists unravel the tapestry of interactions within complex biological networks. Mammalian cells produce thousands of different RNA molecules that do not code for proteins, and their roles remain largely unexplored. Nuñez plans to identify and examine the function of mysterious molecules called long non-coding RNAs, which can promote the growth of cancer cells and stem cells.
Jose M. Orozco, MD, PhDHHMI Hanna Gray Fellow / 2023–Present Dana-Farber Cancer Institute, Inc.
Mentor: Lewis C. Cantley, PhD
Diets high in sugar and carbohydrates trigger an orchestra of adaptations throughout our bodies. If the orchestra is out of tune, diseases such as diabetes can wreak havoc on metabolism, with dire consequences for our health. Jose Orozco is interested in understanding the fundamental mechanisms of how our bodies sense and adapt to sugar and carbohydrates. A better understanding of these adaptations will lead to improved care for metabolic diseases of aging.
Carolina Ortiz Cordero, PhDHHMI Hanna Gray Fellow / 2023–Present Massachusetts Institute of Technology
Mentor: Laura L. Kiessling, PhD
Cell types within the human body display unique signatures of sugar molecules called glycans on their surfaces. In human diseases such as cancer and neuromuscular disorders, cell glycan signatures are significantly altered. Carolina Ortiz Cordero is developing tools to study novel glycan components to discover how changes in glycans affect protein function. Ortiz Cordero hopes that understanding novel glycans will help us gain insight into their function in health and disease, leading to new treatments.
James Osei-Owusu, PhDHHMI Hanna Gray Fellow / 2023–Present Harvard Medical School
Mentor: Andrew Kruse, PhD
Many drugs approved by the US Food and Drug Administration target cell membrane receptors. These receptors transduce extracellular signals into key physiological effects such as neurotransmission, taste, vision, and immune responses. However, abnormal receptor signaling can lead to various diseases. James Osei-Owusu wants to understand the molecular basis of how cell membrane receptors are activated and inhibited. He hopes to exploit these underlying mechanisms to improve drug development and disease treatments.
Adriane Otopalik, PhDHHMI Hanna Gray Fellow / 2018–Present The Rockefeller University
Mentor: Vanessa Ruta, PhD
A male fruit fly performs a rich courtship display to attract females of the same species. He’ll chase a female, tap her abdomen, and vibrate his wings to produce a courtship song. Adriane Otopalik wants to know how the male fly brain has evolved to generate distinct courtship sequences across species. Using tiny electrodes, they'll tune in to conversations between neurons as male flies court potential mates. Otopalik hopes to tease out the neural mechanisms underlying behavioral variation between species.
Louis Parham, PhDHHMI Hanna Gray Fellow / 2023–Present Salk Institute for Biological Studies
Mentor: Christina Towers, PhD
Cellular recycling is intimately linked to the pace of aging in many species. Using a light-regulated tool, Louis Parham aims to manipulate recycling processes in C. elegans – a worm having many genes in common with humans – to determine when, where, and how they control aging. By detailing the mechanisms by which cellular recycling dictates age, Parham will pave the way for the development of therapeutics promoting longer and healthier lives.
Dayna C. Patterson, PhDHHMI Hanna Gray Fellow / 2023–Present Northwestern University
Mentor: Amy C. Rosenzweig, PhD
Metalloenzymes are biological machines that can construct small molecules. Among these small molecules are natural products released from bacteria that harbor insecticidal activity against disease-carrying mosquitoes. Considering the adverse effects of commonly used insecticides on human health, it is imperative to seek safer alternatives. Taking on this challenge, Dayna Patterson aims to characterize a novel bacterial product with insecticidal properties and its primary iron-based metalloenzyme. This research will contribute to the development of safer insecticides.
Nicolás Peláez, PhDHHMI Hanna Gray Fellow / 2017–Present California Institute of Technology
Mentor: Michael Elowitz, PhD
Just a few kinds of signals control the fates of cells that either maintain their stem cell state, divide or differentiate in a developing organism. Nicolás Peláez is investigating whether the timing and dynamics of these signals encode critical information. He plans to figure out how and if the sequence of developmental signals directs embryonic stem cells to transform into more specialized cell types. His findings could help researchers devise ways to repair or replace damaged tissues by directing cells into specific differentiation paths.
Angela Phillips, PhDHHMI Hanna Gray Fellow / 2019–Present University of California, San Francisco Assistant Professor of Microbiology and Immunology
Angela Phillips is unraveling the evolutionary arms race between pathogens and the body’s immune system. Antibodies can neutralize pathogens through genetic mutations, but the new mutation’s effectiveness can depend on previous mutations. Working in yeast, Phillips is hunting for patterns in this variability. Her findings will help researchers learn how the immune system produces antibodies against many different pathogens and could provide clues for designing universal vaccines.
Harold Pimentel, PhDHHMI Hanna Gray Fellow / 2017–Present University of California, Los Angeles Assistant Professor of Computational Medicine and Human Genetics
Harold Pimentel wants to understand the link between genes, RNA, and disease. Scientists know that psychiatric and autoimmune diseases, for example, have complicated genetic roots. But teasing out a role for RNA has been difficult. Pimentel is interested in how people’s genetic variation affects RNA splicing – how cells edit RNA copies of genes. He’s developing computational frameworks to help design and analyze his collaborators’ CRISPR-based experiments as well as large genetic data sets from patients. He hopes to uncover whether differences in RNA splicing lead to different disease outcomes.
Vanessa Puñal, PhDHHMI Hanna Gray Fellow / 2020–Present University of Michigan
Mentor: Josie Clowney, PhD
Vanessa Puñal is examining the development of the brain circuits underlying sensory perception. Brains are wired to detect an ever-changing buffet of sounds, sights, and smells – and to tell them all apart. Like mixing primary colors to paint a rainbow, brain circuits can code for such a wide range of stimuli by mixing and matching inputs from a much smaller number of sensory receptors. In tracking how such a wiring pattern emerges in developing fruit fly brains, Puñal hopes to uncover insights about the organization of sensory perception more broadly.
Sofia Quinodoz, PhDHHMI Hanna Gray Fellow / 2020–Present Princeton University
Mentor: Clifford Brangwynne, PhD
Sofia Quinodoz is unpacking the organization of cells’ nuclei. DNA condensed in the nucleus is strategically packed so that genes can be turned on and off at the right times. Scientists suspect that small droplets called nuclear condensates help guide this packing process, concentrating important proteins and making sure that related genes stick close together. As a doctoral student, Quinodoz developed a new way to map how the nucleus is organized. Now, Quinodoz is applying that technology to better understand how these droplets organize the genome and drive gene regulation.
Joshua Raji, PhDHHMI Hanna Gray Fellow / 2022–Present The Johns Hopkins University
Mentor: Christopher John Potter, PhD
Mosquitoes transmit deadly diseases to humans around the world. The insects rely on their powerful sense of smell to detect humans, and Joshua Raji will exploit this to fight the bites. Raji plans to uncover the molecular targets that drive mosquitoes’ attraction to humans, and the human odors most crucial in activating these targets. Raji’s work could lead to novel ways of controlling mosquito behaviors, and ultimately protect humans from infectious bites.
Valeria M. Reyes Ruiz, PhDHHMI Hanna Gray Fellow / 2020–Present Vanderbilt University Medical Center
Mentor: Eric P. Skaar, PhD
As antibiotic resistance becomes an increasingly urgent public health challenge, Valeria Reyes Ruiz is hunting for new ways to halt deadly Staphylococcus aureus bacterial infections. Her approach: depriving bacteria of the key nutrients they need to survive and spread in the body. Reyes Ruiz will detail how staph bacteria respond to the mineral manganese, and then work out the mechanisms by which immune cells starve bacteria of manganese to fight back. Understanding that interplay may help identify antibiotic-free ways to treat dangerous infections.
Yara Rodriguez Zabala, PhDHHMI Hanna Gray Fellow / 2023–Present Dana-Farber Cancer Institute, Inc.
Mentor: Kimberly Stegmaier, MD
Cancer cells have an Achilles heel – a vulnerability in the form of a gene or biological pathway that they rely on for survival. Yara Rodriguez is working to identify such vulnerabilities in the most aggressive type of blood cancer: acute myeloid leukemia (AML). Using sophisticated molecular biology and gene editing techniques to interrogate AML cells, she aims to uncover targets for their disruption. Identifying these genes or pathways can lead to potential therapies to treat AML patients.
Gabriel Romero, PhDHHMI Hanna Gray Fellow / 2022–Present Harvard Medical School
Mentor: Lisa Goodrich, PhD
In response to stress, we adapt to avoid harm by enhancing the protective abilities and performance of key systems, including the auditory system, which must increase its sensitivity while also preventing itself from failing. By revealing the neural pathways and mechanisms underlying these responses, Gabriel Romero aims to determine how the brain communicates its internal state to the ear, enabling us to dynamically adjust how we detect and react to stimuli in the surrounding world.
Nicolle Rosa Mercado, PhDHHMI Hanna Gray Fellow / 2022–Present The Johns Hopkins University
Mentor: Rachel Green, PhD
Cellular stresses, such as those caused by infection or chronic disease, trigger a general shutdown of protein synthesis. However, proteins that are important for cell recovery or activating programmed cell death continue to be produced. Nicolle Rosa Mercado studies how mRNA dynamics impact the regulation of protein production upon cellular stress. By identifying the targets and effectors of this regulation, Rosa Mercado's work could reveal potential therapeutic targets to treat conditions ranging from neurodegeneration to cancer.
Florentine Rutaganira, PhDHHMI Hanna Gray Fellow / 2017–Present Stanford University Assistant Professor of Biochemistry & Developmental Biology
Florentine Rutaganira wants to use chemical tools to decipher the roles of key signaling networks in choanoflagellates, single-celled organisms that are the closest living relatives of animals. Choanoflagellates produce a large number of tyrosine kinases, molecular signals essential for intercellular communication in animals. The presence of these molecules in choanoflagellates suggests that signaling components needed to communicate between cells is evolutionarily ancient. Tyrosine kinases may regulate choanoflagellate colony formation. Rutaganira expects her studies will spark new understanding of animal development, physiology, and disease.
Francisco J. Sánchez-Rivera, PhDHHMI Hanna Gray Fellow / 2017–Present Massachusetts Institute of Technology Assistant Professor of Biology
The p53 gene is the most commonly mutated gene in human cancers. Francisco J. Sánchez-Rivera plans to comb through human tumor data to systematically identify recurring—but understudied—p53 mutations, and figure out how they wreak havoc in the body. Many of these mutations are known to inactivate the p53 protein and eliminate its role as a tumor suppressor. But Sánchez-Rivera is particularly interested in mutations that create proteins with new abilities. His studies may kindle new therapeutic strategies relevant to a broad range of cancers.
Marissa Scavuzzo, PhDHHMI Hanna Gray Fellow / 2020–Present Case Western Reserve University
Mentor: Paul Tesar, PhD
Marissa Scavuzzo studies the nervous system – the one inside your gut. Using lab-grown organs to mimic the human intestine, Scavuzzo is mapping the diversity of support cells called glia. Glia in the brain regulate and protect neurons in many different ways, but their role in helping gut neurons work smoothly is a new field. Her goal: to understand the many functions of glia in a healthy gut, and then figure out how these cells respond to genetic, environmental, and dietary changes.
Molly Schumer, PhDHHMI Hanna Gray Fellow / 2017–Present Stanford University Assistant Professor of Biology
Biologists once thought that hybridization between species was rare and an evolutionary dead end. But recent advances in genomics have revealed that closely related species frequently exchange genes and pass them on to future generations. Molly Schumer wants to understand how these instances of hybridization shape the evolution of genomes and species. Combining work in the lab and field, she is building an understanding of factors that influence hybrid ancestry in the genome.
Jess Sheu-Gruttadauria, PhDHHMI Hanna Gray Fellow / 2019–Present University of California, San Francisco
Mentor: Ronald Vale, PhD
Jess Sheu-Gruttadauria wants to understand an unusual class of cellular structures – ones that lack confining membranes. These liquid-like organelles may act as an interconnected system, exchanging information via proteins and genetic material. Sheu-Gruttadauria is developing tools that will allow researchers to watch unconfined organelles coordinate their signals in living cells. Misfired signals underlie many neurodegenerative diseases. Decoding the activity and functions of these organelles and their potential role in disease could provide clues to treatment.
Tulika Singh, PhD, MPHHHMI Hanna Gray Fellow / 2023–Present University of California, Berkeley
Mentor: Eva Harris, PhD
Over our lifetimes we experience multiple viral infections. Some infections are similar to ones we have fought earlier. In the best-case scenario of secondary infection, our pre-existing immunity will jumpstart and neutralize the new, but related, virus. Tulika Singh wants to uncover the immune pathways that remember and reactivate such broadly neutralizing antibodies. She is pioneering tools to measure the parts of our immune response that encompass diversity towards multiple viruses. Singh hopes this work will improve vaccine design to protect the world from emerging viruses.
Jarrett Smith, PhDHHMI Hanna Gray Fellow / 2018–Present Whitehead Institute for Biomedical Research
Mentor: David Bartel, PhD
Jarrett Smith wants to understand how stress impacts cells. In stressed cells, many ingredients for protein synthesis clump into enigmatic structures called stress granules. These granules are thought to slow down cells’ protein-making machinery and may be tied to disease – but their exact role is unknown. Smith plans to identify the molecules that compose stress granules and to investigate their effect on cellular function. The results could clarify granules’ link to cancer, viral infection, and neurodegenerative disease.
Quinton Smith, PhDHHMI Hanna Gray Fellow / 2018–Present University of California, Irvine Assistant Professor of Chemical and Biomolecular Engineering
Quinton Smith wants to engineer stem cell-derived “mini livers” in the lab. He plans to recreate the biliary tree, an essential liver structure that secretes digestive enzymes and exports toxins. By incorporating a biliary tree into a mixture of liver-specific cell types, Smith aims to create engineered tissue that grows and responds to regeneration cues in injured mouse livers. He hopes the results will translate into new therapies for humans and offer hope for liver failure patients on the organ donation waiting list.
Zuri Sullivan, PhDHHMI Hanna Gray Fellow / 2020–Present Harvard University
Mentor: Catherine Dulac, PhD
Sick animals often withdraw socially, hiding instead of seeking affection. Zuri Sullivan is hunting for the neural basis of those behavioral changes in the face of illness. Focusing on a recently identified brain circuit that influences whether mice crave social interaction, Sullivan is studying how inflammation affects the neural circuits that shape social behavior in mice. Untangling these interactions will help scientists better understand how the immune system affects behavior.
Simón(e) Sun, PhDHHMI Hanna Gray Fellow / 2023–Present Cold Spring Harbor Laboratory
Mentor: Jessica Tollkuhn, PhD
Simón(e) Sun studies how gonadal hormones contribute to sex-variable neurobiology, with the broad goal of improving sex- and gender-related mental healthcare. The steroid hormones – progesterone, androgens, and estrogens – shape the expression of different sex variable social behaviors such as aggression, mating, and parenting. These behaviors emerge during adolescence, but the mechanisms that direct these hormone-mediated effects are poorly understood. To reveal these mechanisms, Sun is investigating adolescent development in mice at three levels: genomics, neurophysiology, and neurocircuitry.
Jeannette Tenthorey, PhDHHMI Hanna Gray Fellow / 2018–Present University of California, San Francisco Assistant Professor of Cellular & Molecular Pharmacology
Jeannette Tenthorey is investigating how mammals’ immune systems stop bacterial invaders from growing. One family of immune proteins unravels molecular strings that some bacteria use to travel through infected cells. Tenthorey has identified rapidly evolving changes in these immune proteins – a sign that they are mutating to counteract bacterial attempts to evade or destroy them. She plans to determine the specific mutations that help these proteins resist attack. The work could offer new tools for halting bacterial growth.
Maria Toro Moreno, PhDHHMI Hanna Gray Fellow / 2022–Present Fred Hutchinson Cancer Center
Mentors: Harmit S. Malik, PhD, and Arvind Rasi Subramaniam, PhD
Our genomes encode thousands of microproteins with mysterious evolutionary origins and functions. Most research has focused on conserved microproteins, but this excludes rapidly evolving microproteins with potential roles in immunity. Maria Toro Moreno is investigating whether these rapidly evolving microproteins act as defenses against important pathogens such as HIV and influenza. Her research – combining creative evolutionary, high-throughput genomics, and virology approaches – will identify novel antiviral molecules encoded in our genomes and illuminate how they arise throughout evolution.
Ngoc-Han Tran, PhDHHMI Hanna Gray Fellow / 2022–Present Whitehead Institute for Biomedical Research
Mentor: Ruth Lehmann, PhD
The continuity of life rests on faithful inheritance of both DNA and cellular machineries responsible for decoding the genomes. Ngoc-Han Tran studies the endoplasmic reticulum – a cellular compartment that varies in size and shape and performs a wide range of essential functions – throughout its dynamic partitioning in the ovary. By defining the relationship between endoplasmic reticulum shapes and functions during oogenesis, Tran seeks to understand how the endoplasmic reticulum is inherited across generations and how its malfunctions frequently lead to many diseases.
Rudy Urbano, PhDHHMI Hanna Gray Fellow / 2019–Present Yale University
Mentor: Jorge Galán, DVM, PhD
Virulent human pathogens hijack the cell’s movement machinery to travel within cells and spread between cells during infection. Rudy Urbano wants to understand how human cells defend themselves against these microbial tricks. Using advanced imaging and genetic techniques, he’s untangling the mechanisms by which human cells activate proteins to block invaders. This detailed understanding of how cells stymie disease could lead to new strategies for treating infections.
Guillaume Urtecho, PhDHHMI Hanna Gray Fellow / 2020–Present Columbia University
Mentor: Harris Wang, PhD
Probiotics can populate the gut with a bevy of beneficial bacteria – but to be effective, those supplemental microbes need to stick around and multiply, not pass right through. Guillaume Urtecho is studying the genes that enable bacteria to set up shop in the gut. Urtecho plans to survey genetic variations in two different families of enzymes that bacteria use to shape their local environment to figure out which versions make the intestines a more habitable place for the helpful bacteria. The findings could guide the development of more effective probiotic therapies.
Anthony Venida, PhDHHMI Hanna Gray Fellow / 2023–Present Stanford University
Mentor: Michael Bassik, PhD
Anthony Venida is interested in understanding the mechanisms that lead to death of dopaminergic neurons, a major pathological hallmark of Parkinson’s disease. He is studying how protein and organelle quality control mechanisms in the brain become dysfunctional and lead to buildup of toxic factors that cause disease. Using CRISPR-based technology to manipulate gene function and investigating the interplay between neurons and glial cells, he hopes to identify disease-modifying therapies that can prevent neuronal cell death.
Matheus Victor, PhDHHMI Hanna Gray Fellow / 2018–Present Massachusetts Institute of Technology
Mentor: Li-Huei Tsai, PhD
Scientists often rely on mice to probe neurodegenerative diseases. But the neural rules that hold true in mice don’t always translate to humans. Matheus Victor wants to study the genetic mechanisms of Alzheimer’s disease. He’s reprogramming human skin cells in the lab to grow into brain immune cells called microglia. These cells orchestrate inflammatory responses in the brain, a key feature of Alzheimer’s. Victor hopes that the lab-grown microglia will help researchers understand how Alzheimer’s progresses in humans.
Jessica WarrenHHMI Hanna Gray Fellow / 2022–Present Arizona State University
Mentor: John McCutcheon, PhD
Plants are essential for life on Earth. One of the most important features of plant cells is the chloroplast, which originated from the capture of a cyanobacterium approximately a billion years ago and facilitates the process of photosynthesis. Jessica Warren is investigating how the chloroplast’s bacterial structures and genetic features have been integrated into modern plant cells, and how this incorporation controls plant development and physiology.
Shanice Webster, PhDHHMI Hanna Gray Fellow / 2022–Present Duke University
Mentor: Sheng Yang He, PhD
Shanice Webster is examining tritrophic interactions among plants, pathogens, and the microbiome to uncover general principles and mechanistic underpinnings of how pathogens and the microbiome influence each other in plant pathogenesis. Understanding these interactions is critical to understanding disease at a holistic level. Given the importance of plant-microbe interactions to plant health and food security, Webster hopes that her study can lead to new insights and methods of disease interventions to improve global sustainability in the face of climate change.
Alexandra Wells, PhDHHMI Hanna Gray Fellow / 2023–Present The University of Texas Southwestern Medical Center
Mentor: John W. Schoggins, PhD
Viral infections ignite a powerful immune pathway, sounding the alarm within the body about foreign invaders. The proteins induced by this cascade possess remarkable antiviral potential, fueling Alexandra Wells’ mission to uncover how they combat viral infections. Through whole animal approaches, she seeks to discover new antiviral proteins and shed light on their crucial role in countering viral pathogenesis, paving the way for improved models to test therapeutics.
Arielle Woznica, PhDHHMI Hanna Gray Fellow / 2018–Present University of Texas at Austin Assistant Professor in the Department of Molecular Biosciences
Arielle Woznica wants to know what happens when choanoflagellates get sick. These single-celled organisms are the closest living relatives of animals. Discovering viruses that infect choanoflagellates will let Woznica study how they fend off infection. She aims to understand how these organisms – as well as evolutionarily ancient animals including sponges, comb jellies, and sea anemones – sense and respond to viruses. The work could provide insight into the origins and evolution of animal innate immunity, our first-line defense against microbial threats.
Autumn York, PhDHHMI Hanna Gray Fellow / 2017–Present Yale University
Mentor: Richard Flavell, PhD
Unchecked inflammation is the hidden culprit behind many diseases — including inflammatory bowel disease, rheumatoid arthritis, and Alzheimer's. Autumn York is investigating how the immune system interacts with the body’s metabolic pathways to control inflammation. She wants to expose how immune cells sense pathogen-triggered changes in fatty acid synthesis and then relay the message to limit inflammation. Her work may lead to new ways to prevent disease progression and suggest novel strategies to control infection.
Wendy Yue, PhDHHMI Hanna Gray Fellow / 2017–Present University of California, San Francisco
Mentor: David Julius, PhD
Debilitating migraine headaches, which afflict up to 15 percent of the world’s population, are thought to be sparked by nerve cells called trigeminal ganglion neurons. Wendy Yue aims to find out what activates these pain-sensitive cells. By exciting, shutting down, or genetically altering these neurons in mice, Yue will explore their contribution to migraine pain. Her experiments will also clarify whether and how blood vessels participate in the generation of migraine headaches.