Quantitative mapping of a digenic behavioral trait implicates globin variation in C. elegans sensory behaviors

Area of Science:

• Genetics
• Neuroscience
• Behavioral Biology

Background:

• Complex behavioral traits often have a polygenic basis, with limited understanding at the molecular level.
• Environmental factors like oxygen (O2) and carbon dioxide (CO2) significantly influence animal behavior.

Purpose of the Study:

• To identify the genetic underpinnings of differential behavioral responses to environmental O2 and CO2 in C. elegans.
• To elucidate the molecular mechanisms by which specific genes modulate sensory signaling and behavior.

Main Methods:

• Utilized quantitative trait loci (QTL) mapping to identify genetic loci associated with behavioral variation.
• Performed single-gene polymorphism analysis to pinpoint causative genes.
• Investigated gene function through analysis of neuronal signaling, specifically O2-evoked calcium signals.

Main Results:

• Identified two quantitative trait loci (QTL) responsible for opposing behavioral responses to O2 and CO2 in C. elegans strains N2 and CB4856.
• Mapped these QTL to single-gene polymorphisms in npr-1 (neuropeptide receptor) and glb-5 (neuronal globin).
• Demonstrated that glb-5 functions in O2-sensing neurons to modulate calcium signaling and behavioral responses to O2.

Conclusions:

• npr-1 and glb-5 are key genetic determinants of complex behavioral responses to environmental gases in C. elegans.
• The globin gene, glb-5, plays a novel role in sensory transduction, linking gas sensing to behavioral output.
• Alleles of npr-1 and glb-5 may represent recent adaptations to laboratory environments.