Four statistical epistatic interactions associated with mean root length.

<p>(A) The x- and y-axes represent the five <i>A</i>. <i>thaliana</i> chromosomes. The positions of the seven SNPs that are part of the four significant interacting pairs (<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1005541#pgen.1005541.t002" target="_blank">Table 2</a>) are indicated by a black dot. Solid lines indicate support for an interaction by more than one linked SNP and dotted lines indicate support by a single SNP. (B) Genotype-phenotype (G-P) map of the root means for the four genotype combinations constituting the interaction between the SNPs on chromosome 1 (17,257,526 bp) and chromosome 5 (15,862,026 bp). The major allele is indicated by -1, and the minor allele is indicated by 1. This G-P-map is a representative example for the other pairs in which the accessions with a minor and major allele have lower phenotypic values than those with either both major or both minor alleles (<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1005541#pgen.1005541.s003" target="_blank">S2 Fig</a>). (C) G-P map for the most significant epistatic pair illustrates how this type of epistasis cancels the additive genetic variance at the allele-frequencies observed for the two loci in the analyzed population of wild-collected <i>A</i>. <i>thaliana</i> accessions.