Figure 1.

Schematic diagram of human mitochondrial genomic DNA. Mitochondrial DNA is 16,569 bp long. mtDNA encodes 13 mRNAs required to produce components for the electron transport chain complex and 2 rRNAs and 22 tRNAs for mitochondrial translation. D-Loop is the major non-coding region that contains the promoter components called HSP1, HSP2, and LSP. The replication origins of heavy and light strands known as O_H and O_L control the mtDNA replications. Compared with O_H, locating within the D-Loop, O_L is located between the region encoding three tRNAs and the region encoding two other tRNAs. The names of the protein-coding genes are shown in the diagram. LSP = light strand promoter. HSP1 and HSP2 = heavy strand promoters. CSB = conserved sequence block. TAS = termination-associated sequence.