Fig. 3

The distribution of base composition calculated with genic and non-genic SNPs in maize (a) and soybean (b). The upper panel shows the distribution of SNPs across different genomic annotation sets. The middle panel shows the base-composition distribution with genic and non-genic SNPs. The lower panel illustrates the base-composition distribution across 5 Mb segments with genic and non-genic SNPs. To simplify the plot in the lower panel, landraces and improved cultivars are combined to be the domesticated group to compare with the wild group. For each accession, base composition was calculated using a moving average approach with a 5-Mb window size and a 4-Mb step size. Each point in the plot represents the mean [AT] of the specified group across a 5-Mb window. The gray bar in the bottom indicates the position of the pericentromeric region, and the red bar within the gray bar shows the position of the centromeric region