The maternally inherited mitochondrial DNA (mtDNA) is located inside every mitochondrion, in variable number of copies, and it contains 37 crucial genes for cellular bioenergetics. This chapter will discuss the unique features of this circular genome including heteroplasmy, haplogroups, among others, along with the corresponding clinical relevance for each. The discussion also covers the nuclear-encoded mitochondrial genes (N > 1000) and the epistatic interactions between mtDNA and the nuclear genome. Examples of mitochondrial diseases related to specific mtDNA mutation sites of relevance for humans are provided. This chapter aims to provide an overview of mitochondrial genetics as an emerging hot topic for the future of medicine.
Keywords: Epigenetics; Mitochondrial DNA; Mitochondrial haplogroups; Mitonuclear epistatis; Single Nucleotide Polymorphism.