Tissue-Specific Expression Pattern in Ancherythroculter nigrocauda, a Sexually Size Dimorphic Fish

Area of Science:

• * Genomics
• * Fish Biology
• * Aquaculture

Background:

• * Sexual dimorphism (SD) causes significant phenotypic differences between sexes in Actinopterygii fish.
• * Body weight differences are economically important in aquaculture.
• * Ancherythroculter nigrocauda exhibits substantial sexual size dimorphism (SSD), with females reaching fourfold the body weight of males.

Purpose of the Study:

• * To investigate the molecular mechanisms underlying sexual size dimorphism in Ancherythroculter nigrocauda.
• * To identify differentially expressed genes (DEGs) in the liver and brain associated with SSD.

Main Methods:

• * RNA sequencing (RNA-seq) was performed on liver and brain tissues of male and female A. nigrocauda.
• * Differential gene expression analysis was conducted.
• * Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, and Weighted Gene Co-expression Network Analysis (WGCNA) were employed.

Main Results:

• * Sample clustering confirmed clear separation based on sex phenotypes.
• * 2,395 DEGs were identified in the liver and 457 DEGs in the brain.
• * Enrichment analyses implicated PPAR signaling, cytochrome P450, and steroid hormone biosynthesis pathways in SSD. The WGCNA identified a 'green module' significantly correlated with SSD.

Conclusions:

• * The study elucidates the molecular basis of sexual size dimorphism in A. nigrocauda.
• * Identified genes and pathways provide targets for understanding and potentially manipulating growth in aquaculture species.