Behavioral idiosyncrasy reveals genetic control of phenotypic variability

Area of Science:

• Quantitative genetics
• Behavioral genetics
• Neurogenetics

Background:

• Traditional quantitative genetics often overlooks genetic influences on phenotypic variability.
• Understanding genetic contributions to individual-to-individual variation is crucial for a complete picture of genotype-phenotype relationships.

Purpose of the Study:

• To investigate the genetic basis of intragenotypic phenotypic variability.
• To identify genes influencing behavioral variability independently of trait means.

Main Methods:

• Utilized Drosophila inbred lines to measure spontaneous locomotor behavior (handedness).
• Performed genome-wide association study (GWAS) on the degree of intragenotypic variability.
• Validated candidate genes using genetic manipulations (deficiencies, null alleles, RNAi).

Main Results:

• Demonstrated that the degree of behavioral variability is heritable.
• Identified several brain-expressed genes, including Ten-a, that affect variability without altering the mean locomotor behavior.
• Pinpointed a brain region (central complex) involved in modulating behavioral variability.

Conclusions:

• Genetic background significantly impacts an individual's propensity for phenotypic variability.
• Current mean-focused GWAS approaches may miss crucial genotype-phenotype links by ignoring variability.
• This work highlights an underappreciated axis of genetic variation contributing to phenotypic diversity.