Identification of C. elegans Mutants with Enhanced Associative Learning Ability

Abstract

With its stereotyped nervous system and ability to respond to and remember environmental stimuli, including smells, tastes, and temperatures, the nematode Caenorhabditis elegans has been shown to be an excellent model organism with which to study the mechanisms of learning and behavioral plasticity. However, very few large scale screens have been conducted to identify learning mutants and those that have been done have relied on genetic mapping techniques that are often laborious and time consuming. We devised a strategy designed to rapidly uncover mutations associated with enhanced olfactory associative learning in C. elegans through the combination of Mos1-mediated insertional mutagenesis with our positive olfactory association assay. Using Mos1 mutants in the daf-8;fer-1 background, we performed two separate preliminary screens and identified one mutant of interest, daf-10, that was capable of enhanced learning compared to wild-type under a strict conditioning and testing regime. We also report various parameters that affect analyses of olfactory associative learning and can be used to optimize the efficiency and accuracy of future assays. This approach holds great promise for the identification of novel candidate genes and molecules that affect learning in C. elegans, and potentially, those that underlie impaired cognitive function in humans.