Figure 3

Phylogenetic analysis of the SRE. The human sterol regulatory element (SRE) motif and its orthologs were scored for transcription factor binding affinity, with low motif scores indicating low predicted affinity to SRE binding protein (SREBP; see Materials and methods). Because the SRE is present in all the analyzed anthropoid primates (indicated by the red branches in the tree) and absent from the prosimians, rodents, and dog, emergence in the lineage leading to anthropoid primates is the most parsimonious explanation.