Key Points

Introduction: Single-Cell Transcriptomics in Weakly Electric Fish

The MSU Electric Fish Lab has built genomic resources spanning the major weakly electric fish lineages, beginning with the electric eel genome in 2014.
Single-cell RNA-seq (named Science’s Breakthrough of the Year in 2018) reveals cell-type-specific biology that bulk RNA-seq cannot resolve.
In mormyrids, testosterone elongates the EOD by remodeling electrocyte morphology and physiology, retunes knollenorgan electroreceptors, and shifts central corollary discharge timing — all coordinated to keep the sensorimotor loop coherent.
The Losilla & Gallant (2025) paper identified 44 genes of interest, including cytoskeletal, ECM, lipid-metabolism, and ion channel genes — but bulk RNA-seq cannot tell us which cell types drive these signals.
The same neural locus (MCA) appears to handle seasonal, developmental, and evolutionary shifts in CD timing — a striking example of substrate reuse across timescales.
Single-cell transcriptomics is the natural next step to ask which cells in this integrated system carry which molecular signatures of plasticity.

Cocoa-butter implants give a several-day, slow-release androgen exposure with a single Day 0 procedure.
Pre-treatment EOD recordings on Day −1 and Day 0 are the per-fish baselines — every post-implant measurement is interpreted relative to them.
Full dissolution of 11-KT in warm cocoa butter is what makes the dose uniform across animals; rushing this step is the most common avoidable source of variance.
Incise anterior to the anal pore, slightly off the ventral midline, and seal cleanly with Vetbond.
A surface-extruded dose is not a delivered dose — flag the animal in the log.

jsonlite::read_json() loads JSON files as nested R lists; each recording trial is a named list with fields like wave, Rate, temp, and specimenno
EOD duration is defined by a threshold criterion applied to the normalized waveform — the choice of threshold is an analytical decision that must be reported
A metadata CSV that maps files to experimental conditions lets you build a tidy dataset by applying a duration function across all recording sessions
Always verify ANOVA assumptions (Levene’s test for equal variance; Shapiro-Wilk on residuals for normality) before interpreting results