Expression levels of pSMAD1/5/8 in adult mantle edge tissues. Comparisons of the levels of pSMAD1/5/8 between left and right sides of the mantle tissue by western blotting. In the non-coiled shelled limpet Patella vulgata, pSMAD1/5/8 expression levels were not different between left and right sides of the mantle edges. By contrast, in the coiled-shell snail Lymnaea stagnalis (dextral and sinistral), pSMAD1/5/8 expression levels were significantly different (asymmetric) (paired t-test; P<0.05). Expression levels were standardized by dividing the values by those of the left side (P. vulgata, Nipponacmea fuscoviridis, and the dextral strain of L. stagnalis), or by those of the right side (sinistral strain of L. stagnalis). Error bars represent standard deviations.