Sperm competition shapes gene expression and sequence evolution in the ocellated wrasse.

Area of Science:

• Evolutionary biology
• Genomics
• Reproductive biology

Background:

• Sexual dimorphism in gene expression is linked to sexual selection.
• Postmating sexual selection is hypothesized to impact gonadal tissue.
• The ocellated wrasse (Symphodus ocellatus) exhibits three distinct male morphs, offering a model for studying sexual selection.

Purpose of the Study:

• To investigate the role of postmating sexual selection in shaping the gonadal transcriptome.
• To compare gene expression profiles across different male morphs of the ocellated wrasse.
• To explore the relationship between sexual selection, gene expression, and gene sequence evolution.

Main Methods:

• Transcriptomic analysis of gonadal tissue from three male morphs of Symphodus ocellatus.
• Differential gene expression analysis between morphs.
• Analysis of gene sequence evolution rates for male-biased genes.

Main Results:

• Nesting males showed feminized gonadal gene expression compared to satellite males.
• Satellite males exhibited a more masculinized gonadal gene expression profile.
• Sneaker males displayed both de-masculinization and de-feminization of gene expression.
• Male-biased genes showed higher rates of sequence evolution, potentially due to positive selection.

Conclusions:

• Postmating sexual selection significantly influences gonadal gene expression patterns in ocellated wrasse.
• These findings suggest sexual selection can drive higher rates of gene sequence evolution.
• The study highlights the gonadal transcriptome as a key target for sexual selection.