Differential Reflex Activity Determines Claw and Closer Muscle Asymmetry in Developing Lobsters

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Science  18 Jul 1986:
Vol. 233, Issue 4761, pp. 354-356
DOI: 10.1126/science.233.4761.354


The paired claws and closer muscles of the lobster, Homarus americanus, are identical in the early juvenile stages, but subsequently differentiate into a stout crusher claw with only slow fibers and a slender cutter with largely fast fibers. Rearing with different substrates or exercise of the claws revealed that claw laterality is determined in the central nervous system by differential reflex activity in the paired claws; the side with greater activity becomes the crusher, while the contralateral side becomes the cutter.