Genetic background-dependent expression of clec-62 in Caenorhabditis elegans

The pursuit of genes underlying quantitative traits is often accompanied by creating introgression lines (ILs). ILs consist of a single genetic locus introgressed in an otherwise homogeneous background. We previously generated a genome-covering IL panel by introgression of segments of the strain N2 in a CB4856 genetic background. This population complements a previously created IL panel with CB4856 segments in an N2 genetic background. Combining both panels allow the study of the effect of the genetic background at a higher resolution than previously possible with chromosome substitution strains.
We exposed 150 strains of a N2xCB4856 recombinant inbred line population and the two IL panels to a normal growth regime (20oC on standard NGM plates). After 48 hours of grows, we collected the animals, flash froze them and proceeded to isolate RNA. Via qPCR, we measured the expression of clec-62, finding that only in the N2-background population showed QTL. In other words, no QTL were detected in the RIL and reciprocal IL population. Thereby we show the strong role of the genetic background on trait variation.
Here we present a case of either closely-linked loci that were only segregated in one population, or an epistatic interaction depending on the genetic background. We are currently in the process of building a double introgression panel to experimentally test the effect of two combined backgrounds.