ErythronDB Web site. (A) Expression profile for gene query of Aqp8. P indicates proerythroblast; B, basophilic erythroblast; O, polychromatophilic/orthochromatic erythroblasts; and R, reticulocyte. See supplemental Figure 3A for a complete screen shot. (B) Example of a Boolean search strategy to identify differentially expressed transporter molecules. Gene sets expressed at a threshold level in both populations (top left) are functionally restricted based on GO term (bottom left) and then further limited to gene sets that were differentially expressed (right).