Fig. 9. Correlation between S₁ myosin heavy chain (MHC) expression and actin expression. A significant correlation was observed between S₁ MHC expression and actin expression: S₁ MHC expression=0.437+0.716(actin expression), r²=0.537, P<0.0001. This correlation was dominated by the differences between the fast cutter fibers (CT) and the S₁ fibers. When these groups were analyzed separately, a significant correlation was still observed for the cutter fibers (r²=0.643, P<0.009) but not for the S₁ fibers from the crusher claw muscles (r²=0.027, P<0.52).