Comparative transcriptome profiles of four sexually size dimorphic fish.

Area of Science:

• Comparative genomics
• Fish biology
• Molecular evolution

Background:

• Sexual size dimorphism is common in fish, with distinct growth patterns between sexes.
• Understanding the genetic basis of these differences is crucial for aquaculture and evolutionary studies.
• Previous research focused on individual species, leaving common regulatory mechanisms unexplored.

Purpose of the Study:

• To investigate commonalities in regulatory mechanisms underlying sexual size dimorphism across diverse fish species.
• To identify differentially expressed genes (DEGs) associated with sex-specific growth in four representative fish models.
• To provide a foundation for future research on the genetic control of growth dimorphism in fish.

Main Methods:

• RNA sequencing (RNA-seq) was performed on brain and muscle tissues of four fish species: loach, half-smooth tongue sole, yellow catfish, and Nile tilapia.
• Bioinformatic analysis identified differentially expressed genes (DEGs) between males and females in each species.
• Quantitative real-time PCR (qRT-PCR) was used to validate the expression levels of selected genes.

Main Results:

• Transcriptome analysis revealed a significant number of DEGs in both brain and muscle tissues across the four species, ranging from 192 to 4,732 genes.
• Specific gene expression patterns were observed in relation to sexual growth differences.
• Validation using qRT-PCR confirmed the differential expression of key genes.

Conclusions:

• Comparative transcriptome analysis provides valuable insights into the conserved genetic factors regulating sexual size dimorphism in fish.
• The identified DEGs offer potential targets for understanding and manipulating growth differences between sexes.
• This study lays the groundwork for exploring common regulatory pathways governing sexual dimorphism in fish growth.