Lack of TH immunolabeling is suggested to be a morphological indicator of dopaminergic cell loss during the induction of Parkinson’s symptoms in both vertebrates [45,46] and invertebrates such as Drosophila flies [3], the pond snail Lymnaea stagnalis [15], and the worm Lumbricus terrestris [5]. The gene discussed is TH; the disease is Parkinsonism.