CAREER: Mechanisms regulating phenotypic plasticity in a highly social hermaphroditic fish

Idaho State University, Pocatello ID

Investigators

Abstract

This work will advance new knowledge of how the endocrine system of an organism converts signals from the external environment to alter traits that are expressed, a phenomenon known as phenotypic plasticity. This will be accomplished through studying a remarkable natural system, a highly social marine fish, the bluebanded goby, that is sex role reversed and capable of natural sex change as an adult. In response to status instability in their social group, these fish immediately display behavioral changes and over a few days, a complete transformation of their reproductive organs occurs. Multiple biochemical pathways that activate and/or deactivate steroid hormones can rapidly turn on to modulate gene expression so that cells and entire tissues can change future function. By combining traditional approaches and technological advances in disciplines such as analytical chemistry, bio-engineering design, and molecular biology, this project will provide a comprehensive understanding of how steroid hormone signaling can regulate these complex changes. This proposal specifically merges academic trainees from the high school to postdoctoral level to create inclusive learning exchanges. Through enrolling in a multi-year course, students will work toward mentored research and educational goals where they will be encouraged to become knowledge producers rather than consumers, building a strong foundation for future scientific pursuit. This project will build scientific literacy in the general population through education enrichment modules. The phenome, a set of all observable traits expressed by a cell, tissue, organ, organism, or species, is often tightly coupled via strong selection with changes in the physical and/or social environment. This project investigates mechanisms by which endocrine-network molecules transduce dynamic signals in the social environment to regulate both rapid and long-term phenotypic responses during complex life history transitions. Lythrypnus dalli are a bi-directionally hermaphroditic fish species that have environmental sex determination. Stable social groups comprise of harems with a sex role reversed male at the top of the hierarchy that provides paternal care through intense fanning and rubbing of eggs. In response to social instability, the most dominant female exhibits heightened aggression and territoriality, initiates parenting, and changes gonadal morphology. Each of the three aims of the project will address a different level of biological organization that converges technical and conceptual knowledge to study the initiation and maintenance of phenotypes in stable and sex changing fish: 1) discern post-translational mechanisms by which steroidogenic enzymes regulate sex steroid synthesis, 2) determine the steroid signaling mechanisms that regulate fin kinematics during parenting, and 3) determine the spatio-temporal patterns of gene regulatory networks. The third aim will be accomplished through a Vertically Integrated Project course wherein undergraduate students will work in small groups under peer-based mentorship to discover the anatomical distribution of endocrine and developmental genes. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.