The mitochondrial genome refers to the genetic material found in the mitochondria, the energy-producing structures within cells. Unlike the nuclear genome, which is located in the cell nucleus, the mitochondrial genome is circular and inherited maternally. It contains genes essential for the production of proteins involved in cellular respiration and energy metabolism. Mitochondrial DNA (mtDNA) is relatively small, typically consisting of about 16,500 base pairs in humans. Mutations in the mitochondrial genome can lead to various diseases and are also used in studies of evolution and ancestry, as they provide insights into maternal lineage and population genetics.