Mouse whole genome microarray M/A scatter plots. A) 12.5 dpc – 11.5 dpc. B) 13.5 dpc – 12.5 dpc. C) 13.5 dpc – 11.5 dpc. M represents the log ratio of the two dyes and A represents the average Log2 intensity. Yellow spots with blue outline indicate the expression data for selected genes. The dashed blue line indicates a fold difference of zero representing no differential expression between the two samples analysed. The dashed orange line indicates a average Log2 intensity (A) of 6, representing the background signal intensity.