%0 Journal Article %T Natural variation in gene expression in the early development of dauer larvae of Caenorhabditis elegans %A Simon C Harvey %A Gary LA Barker %A Alison Shorto %A Mark E Viney %J BMC Genomics %D 2009 %I BioMed Central %R 10.1186/1471-2164-10-325 %X There were substantial transcriptional differences between four C. elegans lines under the same environmental conditions. The expression of approximately 2,000 genes differed between genetically different lines, with each line showing a largely line-specific transcriptional profile. The expression of genes that are markers of larval moulting suggested that the lines may be developing at different rates. The expression of a total of 89 genes was putatively affected by dauer larva or non-dauer larva-inducing conditions. Among the upstream regions of these genes there was an over-representation of DAF-16-binding motifs.Under the same environmental conditions genetically different lines of C. elegans had substantial transcriptional differences. This variation may be due to differences in the developmental rates of the lines. Different environmental conditions had a rather smaller effect on transcription. The preponderance of DAF-16-binding motifs upstream of these genes was consistent with these genes playing a key role in the decision between development into dauer or into non-dauer larvae. There was little overlap between the genes whose expression was affected by environmental conditions and previously identified loci involved in the plasticity of dauer larva development.Developmental decisions and processes can be controlled transcriptionally. The free-living nematode Caenorhabditis elegans makes a developmental decision between different larval fates. This decision is based on the 'suitability' of the environment for growth and reproduction. Under 'favourable' conditions, second stage larvae (L2) develop via two larval stages (L3, L4) into reproductive adults [1,2]. However, under 'unfavourable' conditions, L2s form a developmentally arrested L3 stage, the so-called dauer larva. Dauer larvae are environmentally resistant, have a specialised metabolism and are comparatively long-lived [2]. Overall, dauer larvae are transcriptionally repressed compared with actively %U http://www.biomedcentral.com/1471-2164/10/325