Biochemical genetic evidence for a hybrid origin of spined loach, Cobitis taenia taenia, in Japan

Starch gel electrophoresis and isoelectric focusing were performed on sarcoplasmic proteins from three taxa of cobitid fish in Japan, Cobitis biwae, C. taenia striata and C. l. taenia. These taxa are hardly distinguishable from each other by external appearance or morphological characters. Electrophoretic patterns of sarcoplasmic proteins from white muscle suggested fixed allelic differences between C. biwae and C. t. striata at two protein‐coding loci (parvalbumin and creatine kinase). The third taxon, C. t. taenia, showed composite banding patterns with respect to the above two proteins, suggesting C. t, taenia originated from hybridization between C. biwae and C, t. striata. Previously, C. t, taenia and C. t. striata were believed to have shared a common ancestor subsequent to their divergence from C. biwae.