# Exploiting unicellular animal relatives to understand the evolution of sensory systems

> **NIH NIH F32** · HARVARD UNIVERSITY · 2024 · $73,408

## Abstract

PROJECT SUMMARY
Multicellular nervous systems allow animals to sense and respond to their specific environments. Yet animals
evolved from unicellular eukaryotes, in which a single cell must carry out signal transduction from sensation to
behavior. Therefore, understanding how unicellular eukaryotes sense and transduce important environmental
cues into specific behaviors can reveal foundational principles of cellular signaling upon which animal
multicellular sensory systems are built. Choanoflagellates (choanos) are a diverse group of micro-eukaryotes
that are the closest living relatives of animals. Choanos are bacterivorous, requiring them to sense and navigate
changes in pH, oxygen, and metabolites within their environment to find bacterial prey. Choanos have diversified
to occupy a range of aquatic habitats, providing an opportunity to understand how their sensory mechanisms
evolve to meet the demands of diverse ecologies. Furthermore, while typically unicellular, some choanos also
have simple multicellular forms. Here, I propose to investigate how unicellular organisms detect and respond to
a range of environmental cues and how these sensory systems evolve in conjunction with diverse ecologies and
the innovation of multicellularity. This project builds on my expertise in bioinformatics, microscopy, and choano
genetics, while learning new skills in electrophysiology and the biochemistry of sensory systems in the lab of Dr.
Nicholas Bellono (Harvard MCB), who has pioneered physiological studies of sensory systems in non-traditional
model organisms such as sharks, octopuses, anemones, and more. I plan to uncover fundamental principles of
sensory biology and signal transduction, as well as to help reconstruct the types of sensory systems found in the
unicellular ancestors of animals. I will be aided by an interdisciplinary advisory team, including my co-sponsor
Dr. Richard Losick (Harvard MCB), a rigorous molecular biologist who will push me towards a mechanistic
understanding of my system. I will also collaborate with Dr. Agnese Seminara (Univeristy of Genoa), a
biophysicist specializing in fluid dynamics and decision-making, as well as Dr. Ryan Nett (Harvard MCB), an
expert on small molecule isolation and characterization. I will characterize choano behavior and physiology in
response to pH, oxygen, and bacterial metabolites, using electrophysiology and genetically encoded Ca2+
indicator strains (Aim 1). I will identify the receptors mediating these sensory systems and use gene family
evolution analyses to explore how these choano receptor families have diversified in response to divergent
aquatic environments (Aim 2). Finally, I will explore how choanos integrate multiple simultaneous sensory cues
(e.g. pH and oxygen) in both their unicellular and multicellular forms to understand how multicellular evolution
drives the innovation and integration of sensory systems, essential for animal origins.

## Key facts

- **NIH application ID:** 10997473
- **Project number:** 1F32GM156012-01
- **Recipient organization:** HARVARD UNIVERSITY
- **Principal Investigator:** Maxwell Clark Coyle
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $73,408
- **Award type:** 1
- **Project period:** 2024-07-01 → 2027-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10997473

## Citation

> US National Institutes of Health, RePORTER application 10997473, Exploiting unicellular animal relatives to understand the evolution of sensory systems (1F32GM156012-01). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10997473. Licensed CC0.

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