Conditional expression explains molecular evolution of social genes in a microbe.

Area of Science:

• Evolutionary biology
• Molecular evolution
• Social behavior genetics

Background:

• Conflict is a known driver of social trait evolution and biodiversity.
• The impact of conflict on the molecular evolution of social genes remains poorly understood.

Purpose of the Study:

• To investigate the genome-wide effects of social interactions on molecular evolution.
• To determine if conflict drives evolutionary patterns in social genes.

Main Methods:

• Analysis of genome sequences from 67 Dictyostelium discoideum strains.
• Examination of polymorphism and evolutionary rates in social genes.

Main Results:

• Social genes display elevated polymorphism and accelerated evolution.
• These patterns are attributed to relaxed purifying selection, not conflict.
• The "Red King process" describes how intermittent gene activity dilutes selection, increasing drift.

Conclusions:

• Social interactions in Dictyostelium discoideum do not primarily evolve through conflict.
• Relaxed purifying selection, driven by the conditional nature of social gene expression, shapes social gene evolution.
• The Red King process offers a novel explanation for polymorphism and accelerated evolution in social genes.