 A whole-genome duplication event in the teleost lineage allowed for the neofunctionalization of the voltage-gated sodium channel gene Scn4aa which produces electric discharges.In all clades except "Apteronotus" (Latin America), where the cells are derived from neural tissue, the electrocytes are derived from skeletal muscle.Electrocytes, electroplaques or electroplaxes are cells used by electric eels, rays, and other fish for electrogenesis.