Electric organs have evolved at least six times in various teleost and elasmobranch fish. Notably, they have convergently evolved in the African Mormyridae and South American Gymnotidae groups of electric fish. The two groups are distantly related, as they shared a common ancestor before the supercontinent Gondwana split into the American and African continents, leading to the divergence of the two groups. 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.