Ten years of life in compost: Temporal and spatial variation of North German Caenorhabditis elegans populations

Abstract

The nematode Caenorhabditis elegans is a central laboratory model system in almost all biological disciplines, yet its natural life history and population biology are largely unexplored. Such information is essential for in-depth understanding of the nematode's biology because its natural ecology provides the context, in which its traits and the underlying molecular mechanisms evolved. We characterized natural phenotypic and genetic variation among North German C. elegans isolates. We used the unique opportunity to compare samples collected 10 years apart from the same compost heap and additionally included recent samples for this and a second site, collected across a 1.5-year period. Our analysis revealed significant population genetic differentiation between locations, across the 10-year time period, but for only one location a trend across the shorter time frame. Significant variation was similarly found for phenotypic traits of likely importance in nature, such as choice behavior and population growth in the presence of pathogens or naturally associated bacteria. Phenotypic variation was significantly influenced by C. elegans genotype, time of isolation, and sampling site. The here studied C. elegans isolates may provide a valuable, genetically variable resource for future dissection of naturally relevant gene functions. Our study characterizes short-term and long-term natural variation for the model nematode Caenorhabditis elegans, for which the natural life history is surprisingly poorly characterized. Long-term and to a lesser extent short-term differences are found for both genotypic variation and also two types of ecologically relevant phenotypes, population growth and bacterial choice behavior. The considered C. elegans isolates should provide a valuable resource for future dissection of naturally relevant gene functions.