Expression Divergence in Response to Sex-biased Selection.

Area of Science:

• Evolutionary biology
• Genetics
• Molecular biology

Background:

• Sexual dimorphism, the distinct differences between males and females, is a key evolutionary outcome.
• Intersexual genetic constraints, where genes affect both sexes, may limit the evolution of greater sexual dimorphism.

Purpose of the Study:

• To investigate how breaking intersexual genetic constraints affects the evolution of sexual dimorphism in gene expression.
• To understand the role of shared gene pools in shaping sex-specific adaptations.

Main Methods:

• Experimental evolution in Drosophila melanogaster over 100 generations.
• Utilizing a dominant marker (DsRed) for father-to-son inheritance of "Red" chromosomes, creating a partially separated gene pool.
• Comparing gene expression and splicing patterns between flies with and without "Red" chromosomes.

Main Results:

• "Red" male-limited chromosomes enhanced male mating success.
• Genes with differential expression showed higher intersexual genetic correlations, suggesting constraints.
• Splicing patterns in "Red" males were masculinized, while overall gene expression was feminized in both sexes.

Conclusions:

• Partially breaking intersexual genetic constraints influences the evolution of sexual dimorphism in gene expression and splicing.
• Observed patterns suggest complex interactions, potentially involving intralocus sexual conflict, in shaping sex-specific traits.