Internal Morphological Effects of Growth Hormone Transgenesis in Coho Salmon

Effects of growth hormone (GH) overexpression on internal morphology were examined in homozygous and hemizygous GH transgenic Coho Salmon Oncorhynchus kisutch aided by clearing and staining and magnetic resonance imaging methodologies. Morphological effects of transgenesis were observed in pin bones in fast‐growing hemizygous transgenic salmon, in vertebral column and swim bladder deformities in homozygotes, and as nonproportional modifications to some cranial structures examined among groups. These data provide further examples of the complex pleiotropic effects arising from GH overexpression in transgenic salmon.