Similarity of expression patterns among tissues. (a) Proportion of 192 genes that are similarly expressed between heart and brain (black bar), brain and liver (gray bar) and liver and heart (white bar), for each population including Maine (ME), New Jersey (NJ) and Georgia (GA). (b) Neighbor-joining trees of global similarity of expression patterns among samples (L, liver; H, heart; B, brain) for each population. Distance between samples is the sum of differences of log2 expression values over all genes.
Whitehead and Crawford Genome Biology 2005 6:R13 doi:10.1186/gb-2005-6-2-r13