PhD thesis - Biologisk Institut - Københavns Universitet

23 Resultsobtained fragments were too short to generate riboprobes for successful in situhybridisation experiments.Establishment of an in situ hybridisation protocolUsing a set of degenerate primers (Table 2), gene fragments of 700 bp of myosinheavy chain (Tp-mhc) and 500 bp of beta-actin (Tp-actin) were recovered by PCR.Tp-mhc is expressed from early trochophore stages (ca. 2 days afterfertilisation (dpf)) onwards in the four developing retractor muscles (Fig. 3A-C). FirstTp-actin expression is also in the early trochophore larvae in a prominent U-shapedband in the area of the forming retractor muscles (Fig. 3D). In pelagosphera larvae theTp-actin is expressed in distinct areas of the paired dorsal and ventral retractormuscles (Fig. 3E, F).