Natural diversity of the caenorhabditis elegans satiety quiescence behaviour

Abstract

Natural selection favours organisms that are flexible in the face of changing environmental conditions, a trait that animals achieve by modifying their behaviour. Some of this flexibility arises from the activity of feeding related genes capable of controlling multiple behaviours in a functionally coherent way in response to environmental challenges. As such, these genes are promising targets for studies of the evolution of behaviour. However, while classical genetics can identify the genes themselves, it cannot find the alleles relevant for evolution in the wild. To study the natural variation of feeding behaviour, I investigated the satiety quiescence behaviour of Caenorhabditis elegans by recording a dataset of almost 5000 high-resolution videos of individual worms. The satiety quiescence behaviour is known to have significant genetic overlap with the mammalian postprandial somnolence behaviour, or ‘food coma’, so some of the genes are expected to be conserved and potentially provide insight into the human behaviour, as well. The almost 200 strains tested are from the Caenorhabditis elegans Natural Diversity Resource (CeNDR), a collection of wild type isolates that includes the full genome sequence of each strain in addition to other information. As satiety quiescence is a complex phenotype, I created an analytical pipeline that uses high resolution tracking and multidimensional phenotyping to break the trait down into its parts. This process is successful in identifying several new hypotheses about the way the behaviour itself is organised and controlled. The phenotypic components are then individually associated with genetic variants using genome-wide association mapping, revealing potential new genomic locations related to satiety quiescence.