Selection and gene flow shape niche-associated variation in pheromone response

Area of Science:

• Evolutionary Biology
• Genetics
• Animal Behavior

Background:

• Chemical communication is vital for social interactions in many species.
• In *C. elegans*, ascaroside pheromones regulate population density, inhibiting reproduction at high levels.
• Natural genetic diversity's impact on pheromone response is poorly understood.

Purpose of the Study:

• To investigate how natural genetic variation affects *C. elegans* pheromone responses.
• To identify genetic mechanisms underlying differences in pheromone sensitivity across diverse habitats.

Main Methods:

• Analysis of pheromone receptor genes (*srg-36*, *srg-37*) for loss-of-function deletions.
• Investigating the evolutionary history and global distribution of identified genetic variations.
• Assessing the relationship between genetic genotypes and population dynamics/niche diversity.

Main Results:

• Identified deletions in *srg-36* and *srg-37* impair pheromone receptor function.
• A recent, globally distributed deletion in *srg-37* reduces pheromone sensitivity in *C. elegans*.
• Balancing selection maintains both wild-type and deletion alleles of *srg-37* in natural populations, linked to niche diversity.

Conclusions:

• Niche-associated variation in pheromone receptor genes drives natural differences in pheromone response.
• The *srg-37* deletion's maintenance suggests a role in adapting to fluctuating population dynamics.
• Human activities may have influenced the spread and selection of *srg-37* variation through species migration and habitat modification.