Widespread genomic incompatibilities in Caenorhabditis elegans.
Bottom Line: For two of the QTL regions, results are inconsistent with a model of pairwise interaction between two loci, suggesting that the incompatibilities are a consequence of complex interactions between multiple loci.Analysis of additional life history traits indicates that the QTL regions identified in these screens are associated with effects on other traits such as lifespan and reproduction, suggesting that the incompatibilities are likely to be deleterious.Taken together, these results indicate that numerous BDM incompatibilities that could contribute to reproductive isolation can be detected and mapped within C. elegans.
Affiliation: Laboratory of Nematology, Wageningen University, 6708 PB Wageningen, The Netherlands.Show MeSH
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Mentions: The phenotypic distribution in both the RILs and ILs shows a one-sided transgression, with many genotypes laying large proportions of their eggs at much later stages (Figure 1 and Figure S1) than either of the parental isolates. About half of the RILs laid 50% or more eggs at stage III or later, with about 20% of the ILs displaying such extreme phenotypes (Figure 1). These lines therefore phenocopy mild egl mutations, i.e., they would be classified as M/E, most/early, with all or most progeny released, a few early-stage eggs, and many late-stage eggs observed on the plate (Trent et al. 1983). The observed transgression therefore provides evidence that the stage at which an egg is deposited is a polygenic trait. Moreover, it suggests that either N2 or CB4856 each carry positive and negative allele(s) of the genes involved that are acting additively, or that the observed effects are a consequence of incompatibilities between diverged N2 and CB4856 alleles at different loci, i.e., negative epistatic effects, or a combination of both of these. That more RILs than ILs show an egl phenotype, suggests that multiple regions of the genome and interactions between those contribute to the laying of late stage eggs (comparison between Figure 1, A and B).
Affiliation: Laboratory of Nematology, Wageningen University, 6708 PB Wageningen, The Netherlands.