Gene expression and methylation differences between populations and across generations. a. Heat map, showing the clustering of 242 differentially expressed genes, comparing parental Red Junglefowl (RJF) and White Leghorn (WL) layers, and their offspring. b. Heat map, showing clusters of differentially methylated genes comparing parental RJF and WL, and their offspring. Note that the gene set in b is not the same as in a. c. Average methylation levels (signal intensity from the microarray) for RJF and WL in the 145 promoter regions included in the heatmap in panel b. Circle-diagram displays the percentage of the promoter regions which were hypermethylated (green) and hypomethylated (red) in White Leghorns.