The goal of the Hanna H. Gray Fellows Program is to recruit and retain individuals from gender, racial, ethnic, and other groups underrepresented in the life sciences, including those individuals from disadvantaged backgrounds. Through their successful careers, HHMI Hanna Gray Fellows will become leaders in academic research and inspire 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.

Hanna Gray Fellows at HHMI Headquarters during the Hanna Gray Fellows Retreat 2019

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.


The program application is open to individuals who:

  • are from gender, racial, ethnic, and other groups underrepresented in the life sciences, including those individuals from disadvantaged backgrounds. This includes, but is not limited to, women of any ethnic or racial group as well as any individual identifying as Hispanic, Black, Native Hawaiian / Pacific Islander, or American Indian / Alaska Native.
  • are basic science researchers and physician-scientists in the biomedical and life science disciplines.
  • hold a PhD and/or MD (or equivalent), which must be conferred by the start of the grant term.
    • U.S. citizens must have a degree from a research institution in the U.S. (including Puerto Rico) or an international research institution.
    • Non-U.S. citizens and applicants with other nationalities must have a degree from a research institution in the U.S. (including Puerto Rico).
  • have been accepted to join a laboratory as a postdoctoral researcher at a research institution located in the U.S. (including Puerto Rico) at the time of the application due date.

PhD applicants can have no more than 27 months of postdoctoral research experience at the time of the application due date.

  • The date or anticipated date of conferral of the doctoral degree must be on or after September 1, 2019, and before January 17, 2023.

MD or MD/PhD applicants in residency, clinical fellowship, or postdoctoral training can have no more than 27 months of postdoctoral training by December 1, 2021.

  • For the purposes of this award, research activities during residency or clinical fellowship are not considered postdoctoral training.

The postdoctoral training mentor must hold a tenured or tenure-track position (or equivalent) at an institution in the U.S. (including Puerto Rico).

Components of the Application

  • Summary of the applicant’s educational and training record
  • Personal statement relating past experiences and career goals
  • Overview of the applicant’s prior research experience
  • A list of publications with statements of significance
  • Summary of the applicant’s planned research for postdoctoral phase
  • An evaluative statement provided by the applicant’s research training mentor
  • A statement of support with a training plan provided by the postdoctoral training mentor
  • A curriculum vitae and list of prior trainees provided by the postdoctoral training mentor
  • One additional letter of reference

Postdoctoral Training Phase

Fellows will receive annual support of a $70,000 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.

Faculty Phase

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.

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  • Biafra Ahanonu, PhD

    HHMI 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, PhD

    HHMI Hanna Gray Fellow / 2018–Present University of Minnesota

    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, PhD

    HHMI 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, DPhil

    HHMI Hanna Gray Fellow / 2020–Present University of California, Berkeley

    Mentor: Gary Karpen, PhD

    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, PhD

    HHMI 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.

  • Christopher Barnes, PhD

    HHMI 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.

  • Christopher Bartley, MD, PhD

    HHMI Hanna Gray Fellow / 2019–Present University of California, San Francisco

    Mentors: Samuel Pleasure, MD, PhD and Michael Wilson, MD

    Our immune systems produce antibodies to protect us from infectious microbes, but sometimes these antibodies can target our own organs. Antibodies that mistakenly attack the brain can trigger psychiatric symptoms. Christopher Bartley suspects that such mistargeted antibodies can help us to understand some psychiatric illnesses. A physician and researcher, Bartley will study samples from hundreds of people with schizophrenia to discover new misdirected antibodies. This work could ultimately lead to new targets for psychiatric drugs.

  • Neville P. Bethel, PhD

    HHMI 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, PhD

    HHMI 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.

  • María Angélica Bravo Núñez, PhD

    HHMI 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, PhD

    HHMI Hanna Gray Fellow / 2017–Present The University of Texas Southwestern Medical Center

    Mentor: Lora Hooper, PhD

    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.

  • Elsy Buitrago-Delgado, PhD

    HHMI 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.

  • Kyle Card, PhD

    HHMI 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, PhD

    HHMI 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, PhD

    HHMI 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, PhD

    HHMI Hanna Gray Fellow / 2018–Present Stanford University

    Mentor: Michael A. Fischbach, PhD

    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.

  • Kevin Cox Jr., PhD

    HHMI 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, PhD

    HHMI Hanna Gray Fellow / 2020–Present University of California, San Francisco

    Mentor: James Fraser, PhD

    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.

  • Cesar De Leon, PhD

    HHMI Hanna Gray Fellow / 2019–Present Yale University

    Mentor: Craig Crews, PhD

    Cesar De Leon is designing a new class of antibiotics to help cells send invasive bacteria to the cellular garbage disposal. He’s targeting Gram-negative bacteria, which can cause deadly diseases and are impervious to many current antibiotics. De Leon aims to make molecules that boost a natural cellular defense process for breaking down pathogens. He hopes his molecules will selectively flag tricky microbes for faster destruction – without hurting beneficial bacteria.

  • Emily Dennis, PhD

    HHMI Hanna Gray Fellow / 2019–Present Princeton University

    Mentor: Carlos Brody, PhD

    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.

  • Kelsie Eichel, PhD

    HHMI 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.

  • Carolyn Elya, PhD

    HHMI 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.

  • Chantell Evans, PhD

    HHMI 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, PhD

    HHMI Hanna Gray Fellow / 2018–Present University of Southern California

    Mentor: Gage Crump, PhD

    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, PhD

    HHMI 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.

  • Morgan Gilman, PhD

    HHMI 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, PhD

    HHMI 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, PhD

    HHMI 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.

  • Arif Hamid, PhD

    HHMI Hanna Gray Fellow / 2017–Present Brown University

    Mentor: Christopher Moore, PhD

    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.

  • Autumn Holmes, PhD

    HHMI 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.

  • Adrian Jinich, PhD

    HHMI 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.

  • Kalli Kappel, PhD

    HHMI 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.

  • Silvana Konermann, PhD

    HHMI Hanna Gray Fellow / 2017–Present Stanford University Assistant Professor of Biochemistry

    With powerful new genetic tools, Silvana Konermann plans to untangle the complex web of genes that predispose a person to Alzheimer’s disease. One of the strongest genetic risk factors for the neurodegenerative disease is a gene called APOE. Carrying the APOE4 version of the gene increases risk, while the APOE2 version is protective. Using a gene editing technology called CRISPR-Cas9, Konermann plans to systematically knock out parts of the genome as she hunts for other genes that interact with APOE.

  • Caitlin Mallory, PhD

    HHMI 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, PhD

    HHMI Hanna Gray Fellow / 2020–Present The University of North Carolina at Chapel Hill

    Mentor: Ralph Baric, PhD

    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.

  • Pablo Martinez, PhD

    HHMI Hanna Gray Fellow / 2019–Present University of California, Los Angeles

    Mentor: Siobhan Braybrook, PhD

    In nature, form is linked to function. A leaf’s flat surface, for example, is well suited to capturing sunlight for photosynthesis. Pablo Martinez is untangling the complex mechanisms by which plants take on different shapes. He’s watching developing maize leaves up close, hoping to reveal how plants respond to physical and mechanical strain caused by dividing and expanding cells. Answering this fundamental question will help scientists understand how crops – and potentially even animals and bacteria – grow and develop. 

  • Melanie McReynolds, PhD

    HHMI Hanna Gray Fellow / 2018–Present Princeton University

    Mentor: Joshua Rabinowitz, MD, PhD

    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.

  • Edgar Medina, PhD

    HHMI 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, PhD

    HHMI 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.

  • Tessa Montague, PhD

    HHMI 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.

  • Evert Njomen, PhD

    HHMI 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, PhD

    HHMI 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.

  • Adriane Otopalik, PhD

    HHMI 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.

  • Nicolás Peláez, PhD

    HHMI 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, PhD

    HHMI Hanna Gray Fellow / 2019–Present Harvard University

    Mentor: Michael Desai, PhD

    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, PhD

    HHMI 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, PhD

    HHMI 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, PhD

    HHMI 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.

  • Valeria M. Reyes Ruiz, PhD

    HHMI 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.

  • Florentine Rutaganira, PhD

    HHMI Hanna Gray Fellow / 2017–Present University of California, Berkeley

    Mentor: Nicole King, PhD

    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, PhD

    HHMI Hanna Gray Fellow / 2017–Present Memorial Sloan Kettering Cancer Center

    Mentor: Scott Lowe, PhD

    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, PhD

    HHMI 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, PhD

    HHMI 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, PhD

    HHMI 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.

  • Jarrett Smith, PhD

    HHMI 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, PhD

    HHMI 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, PhD

    HHMI 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.

  • Jeannette Tenthorey, PhD

    HHMI Hanna Gray Fellow / 2018–Present Fred Hutchinson Cancer Research Center

    Mentor: Harmit Malik, PhD

    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.

  • Rudy Urbano, PhD

    HHMI Hanna Gray Fellow / 2019–Present Yale University

    Mentor: John D. MacMicking, 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, PhD

    HHMI 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.

  • Matheus Victor, PhD

    HHMI 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.

  • Arielle Woznica, PhD

    HHMI Hanna Gray Fellow / 2018–Present The University of Texas Southwestern Medical Center

    Mentor: Julie Pfeiffer, PhD

    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, PhD

    HHMI 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, PhD

    HHMI 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.


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  • December 1, 2021
    Applications due
  • December 8, 2021
    Mentor and reference letters due
  • Late April 2022
    Notification of status
  • June 26-29, 2022
    Finalist symposium
  • Early July 2022
    Notification of awardees
  • Mid-July 2022
    Intent to accept award due
  • September 20, 2022
    Earliest grant start date
  • January 17, 2023
    Latest grant start date

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