Figure 2. The phylogenetic instability of the 59 human Cyp proteins.

The vertical dashed line separates the stable from the unstable sequences. “Substrate” indicates those proteins with primarily endogenous roles (filled squares), primarily xenobiotic roles (empty circles), both xenobiotic and endogenous roles (empty squares), and pseudogenes (P). “Selection” indicates which of the 18 sequences tested showed evidence of positive selection (+), or no positive selection (−). In the “Clusters” row, the solid lines indicate those genes that are located in tandem arrays in the human genome or are syntenic with a tandem array in the mouse genome (S). All substrate, positive selection, and clustering data were taken from (Thomas, 2007).