Abstract:
Previous investigation into the plasticity of Caenorhabditis elegans (C. elegans) endoderm development had revealed broad variation in the requirement for the key regulatory input, SKN-1. SKN-1 is an essential transcription factor which functions within the endomesoderm gene regulatory network (GRN) to specify the fate of endoderm. Testing the requirement for SKN-1 was achieved via skn-1(RNAi) knock down. An immense amount of variation was seen across all 97 wild-type C. elegans isolates (Yamila Torres Cleuren, personal communication, February 2015), in addition to a strong parent-dependent effect. The research here sought to determine whether parent-of-origin effects (POEs) would be observed when a skn-1 mutant was introgressed into the background of a sample population of wild-type isolates. Backcrossing the skn-1(zu67) mutation from an N2 derived strain, JJ185, into three different wild-type populations was completed through to the F12 generation. Introgressions were completed reciprocally to the F6 generation i.e. the JJ185 hermaphrodite was crossed with a wild-type male and then a cross was initiated between the wild-type hermaphrodites and JJ185 males. POEs were observed between all three different reciprocal events and a variety of potential mechanisms have been proposed that may have led to these effects. In addition an RNAi genetic screen of 13 candidate genes (with previously known function) was performed on skn-1 mutant strains, mom-2 and a sample of the wild-type C. elegans population. The purpose of which, was to determine if any of these genes might account for the variation in SKN-1 dependence that was previously observed. The genetic screen results failed to suggest any causal effect in endoderm development. However, there was evidence to suggest that the candidate gene uba-1 (C47E12.5) affects embryo development differently in different genetic backgrounds. The study of inheritance within C. elegans is an efficient and relatively effective system. The insights gained from these unique model organisms may help in the prediction of genetic risk factors in critical inheritance systems, which could contribute towards the improvement of human health.
