Title Highly epistatic genetic architecture of root length in Arabidopsis thaliana Authors

Efforts to identify loci underlying complex traits generally assume that most genetic variance is additive. This is despite the fact that non-additive genetic effects, such as epistatic interactions and developmental noise, are also likely to make important contributions to the phenotypic variability. Analyses beyond additivity require additional care in the design and collection of data, and introduce significant analytical and computational challenges in the statistical analyses. Here, we have conducted a study that, by focusing on a model complex trait that allows precise phenotyping across many replicates and by applying advanced analytical tools capable of capturing epistatic interactions, overcome these challenges. Specifically, we examined the genetic determinants of Arabidopsis thaliana root length, considering both trait mean and variance. Analysis of narrow-and broad-sense heritability of mean root length identified a large contribution of non-additive variation and a low contribution of additive variation. Also, no loci were found to contribute to mean root length using a standard additive model based genome. CC-BY-NC-ND 4.0 International license peer-reviewed) is the author/funder. It is made available under a The copyright holder for this preprint (which was not . http://dx.doi.org/10.1101/008789 doi: bioRxiv preprint first posted online Sep. 4, 2014;