The ND1, ND4, and ND6 genes encode subunits of the enzyme NADH:ubiquinone oxidoreductase, commonly known as Complex I, which is a critical component of the mitochondrial respiratory chain. These genes are involved in the first step of the electron transport chain, where electrons are transferred from NADH to ubiquinone, contributing to the formation of a proton gradient across the mitochondrial membrane.
