In situ expression of 17 P. maxima ESTs differentially expressed among mantle regions. Panels are cross-sectional views of the mantle. Block arrows orient images with respect to the shell. DM = dorsal mantle, VM = ventral mantle, IF = inner fold, MF = middle fold, OF = outer fold. Expression is indicated in dark blue and arrow heads, alternative coloration is background. ESTs displaying similar localization are represented by a single example. (A-C) PM077, PM037 and PM041 [GH280037, GH279997, GH280001] expressed in the outer epithelium of the dorsal mantle, terminating immediately at the ventral mantle region. (D-E) PM316 [JG697411] expressed along the inner epithelium of the mantle and the distal outer epithelial of the middle fold. (F) PM317 [JG697412] expressed proximally in the outer epithelium of the middle fold and the inner epithelium of the outer fold. (G-H) PM315 [JG697410] is discontinuously expressed below the epithelium of the inner fold and middle fold. (I-J) PM233, PM234 and PM235 [GH280193, GH280194, GH280195] expressed along the inner epithelium of the outer fold. (K) PM241 [GH280201] expressed proximally in inner epithelium of the outer fold. (L) PM238 and PM239 [GH280198, GH280199] predominantly expressed mid-way along the inner epithelium of the outer fold. (M-O) PM273, PM268, PM280 and PM281 [GH280233, GH280228, GH280240, GH280241] expressed throughout the outer epithelium of the outer fold and ventral mantle, terminating immediately at dorsal mantle region. (P) PM265 [GH280225] expressed as described for (M-N) in addition to expression in the inner epithelium of the outer fold.