The goal of this study is to find skate pectoral fin motor neuron markers. Total RNA was extracted from manually sorted pectoral fin MNs, which were retrogradely labeled and tail spinal cord cells. By comparing RNA expression profiles of pectoral fin MNs and tail spinal cord neurons, we could identity general MN, MN columnar, and subset MN pool markers for fin MNs. Overall design: Examination of RNA expression profiles in two different samples: pectoral fin MNs and tail spinal cord cells.