Biology subjects

Hoadley, A. P.

Publications and source records attributed to Hoadley, A. P..

3 recordsLinked to original sources

bioRxiv2026

Cell-type-specific architecture of the hypothalamus in a socially plastic vertebrate

The hypothalamus orchestrates social behaviors by integrating physiological state with environmental information, but the cellular substrates of this plasticity remain unresolved. We combined single-cell and spatial transcriptomics to generate a cell-type map of the hypothalamus in Astatotilapia burtoni, a cichlid fish that forms dynamic social hierarchies. We identified 28 neuronal, glial, neurogenic, and immune cell populations and mapped their organization across hypothalamic nuclei. Social status, sex, and reproductive state engaged coordinated, cell-type-specific transcriptional programs, revealing modular deployment of steroid hormone signaling and plasticity-associated genes. The atlas identified elevated sst1.1 expression in the hypothalamus of dominant males that we localized to the teleost VMH. CRISPR-Cas9 disruption of sst1.1 increased body size, suggesting a role for optimal metabolic and energy allocation. These results define a cellular framework for understanding how hypothalamic plasticity enables flexible social behavior.

neuroscience↗

bioRxiv2021

Control of testes mass by androgen receptor paralogs in a cichlid

Steroid hormones play numerous important and diverse roles in the differentiation and development of vertebrate primary and secondary reproductive characteristics. However, the exact role of androgen receptors (ARs)--which bind circulating androgens--in this regulatory pathway is unclear. Teleost fishes further complicate this question by having two paralogs of AR (AR and AR{beta}) resulting from a duplication of their ancestral genome. We investigated the functional role of these two ARs on testes growth and development by experimentally eliminating receptor function of one or both paralogs using CRISPR/Cas9 genome edited Astatotilapia burtoni, an African cichlid fish. Fish with two or more functional receptor alleles were more likely to be male compared to fish with one or fewer, suggesting that the two paralogs of the receptor may be redundant in regulating early sex determination. In contrast, we found that adult testes size was significantly affected by distinct combinations of mutant and wild-type AR alleles. We present a working model whereby AR{beta} facilitates testes growth and AR causes testes regression. This mechanism may contribute to the robust social and physiological plasticity displayed by A. burtoni and other social teleost fish.

physiology↗

bioRxiv2020

The neuroplasticity of division of labor: worker polymorphism, compound eye structure and brain organization in the leafcutter ant Atta cephalotes

Our understanding of how the design of peripheral sensory structures is coupled with neural processing capacity to adaptively support division of labor is limited. Workers of the remarkably polymorphic fungus-growing ant Atta cephalotes are behaviorally specialized by size: the smallest workers (minims) tend fungi in dark subterranean chambers while larger workers perform tasks mainly outside the nest. These strong differences in worksite light conditions are predicted to influence sensory and processing requirements for vision. We found that eye structure and visual neuropils have been be selected to maximize task performance according to light availability. Minim eyes had few ommatidia, large interommatidial angles and eye parameter values, suggesting selection for visual sensitivity over acuity. Large workers had larger eyes with disproportionally more and larger ommatidia, and smaller interommatidial angles and eye parameter values, reflecting peripheral sensory adaptation to ambient rainforest light. Additionally, optic lobe and mushroom body collar volumes were disproportionately small in minims, and within the optic lobe, lamina and lobula relative volumes increased with worker size whereas the medulla decreased. Visual system phenotypes thus correspond to task specializations in dark or light environments and reflect a functional neuroplasticity underpinning division of labor in this socially complex agricultural ant.

neuroscience↗