Unravelling the Genetic Architecture of Rolling Behavior in the Domestic Pigeon (Columba livia)
Authors: Atoosa Samani; Emily Maclary; Michael Shapiro
Affiliation: The University of Utah
Keywords: Complex traits
Hereditary rolling or tumbling in the domestic pigeon (Columba livia) is a backward somersault behavior that is stimulated by attempting to fly. Rolling has excited the curiosity of scholars for centuries; Darwin describes rolling as “…one of the most remarkable inherited habits or instincts ever recorded”. Rolling is progressive: it does not present itself until a few weeks after fledging and becomes more severe with age. Rolling affects locomotion, but no anatomical anomalies are known to be associated with it. Roller pigeons walk, eat, and breed normally, suggesting that rolling is a specific context-dependent behavior and not a generalized physiological disorder. Rolling is recessive and highly heritable, yet the molecular genetic basis remains unknown. Therefore, rolling offers a unique opportunity to discover the molecular basis of a complex yet genetically tractable behavioral phenotype. Using a combination of quantitative trait locus (QTL) mapping in a laboratory intercross and comparative genomics among pigeon breeds, we identified several loci associated with rolling behavior. Although rolling is a polygenic trait, one major QTL explains 61% of the phenotypic variance in the laboratory cross. Comparisons between the resequenced genomes of rollers and non-rollers confirm the polygenic nature of this behavior, and that quantitative genetic and GWAS approaches yield overlapping results. Dissection of the candidate loci at the gene level will deepen our understanding of the molecular basis of involuntary and task-specific movement disorders and other progressive vertebrate behaviors.