<i>In situ</i> hybridization.

<p><i>In situ</i> hybridization in <i>ace1a</i> in the preadult salmon louse. Bound probe to mRNA fragments on a 3 μm coronal section appear as blue stain. The arrow points to staining in the central ganglion and the arrowhead indicates staining in the intestinal wall. Images on the right panels are a 10-fold magnification of the positive areas.</p>