Fig. 7. Regenerative growth in distal fin regenerates is more sensitive to partial Fgfr inhibition than proximal regenerative growth. (A) Daily exposure of double-amputated hsp70:dn-fgfr1 zebrafish to 36°C heat shock has a significant effect on the growth of proximal and distal fin regenerates. Measurements were averaged from 18 untreated and 21 36°C-treated animals (^*P<0.05, significantly different from no HS, t-test: ^**P<0.001, significantly different from no HS, t-test). (B) Graph of intrafin proximal to distal length ratios using animals described in A. The higher proximal:distal length ratio in 12 dpa 36°C heat-shocked animals indicates a greater sensitivity of distal regenerative growth to partial Fgfr inhibition (^*P<0.001, significantly different from no HS, t-test). (C-E) Representative transgenics at 5 dpa given no HS (C) or 36°C heat shocks (D,E). Arrows indicate points of amputation. Some 36°C transgenics appeared similar to untreated transgenics at early timepoints such as 5 dpa (D), while others showed especially poor distal regeneration (E). Such variability is also reflected by the large standard error bars in B that characterize 36°C P:D ratios at 4 and 8 dpa.