Co

CO 11 ATPase8

Complex I genes (NADH dehydrogenase)

Complex III genes (cytochrome c oxidoreductase)

Complex IV genes (cytochrome c oxidase)

Complex V genes (ATP synthase)

Ribosomal RNA genes

I I Transfer RNA genes

Figure 8.1 Genetic map of human mtDNA and expanded diagram of the D-loop region. The outer circle represents the H-strand, containing the majority of the genes; the inner circle represents the L-strand. The origins of replication for H-strand (OH) and L-strand (OL), and the promoters for H-strand (HSP) and L-strand (LSP), are shown by the arrows. The 22 tRNA genes are depicted by the single-letter code of the amino acid (isoacceptors for serine and leucine are distinguished by their codon sequence). The D-loop region diagram shows flanking tRNAs and location of hypervariable regions HV-I and HV-II; numbering system follows that of the CRS

vary by one or more bases owing to deletions, insertions or repetition. The control region contains the binding sites for the major promoters of transcription and the origin of H-strand replication (OH) (Taanman, 1999). This region also contains the HV-I and HV-II polymorphic regions. The HV-I ranges from position 16 024 to 16 365, and HV-II ranges from position 73 to 340. These hypervariable regions represent ongoing mutational hotspots rather than the remnant of previously incorporated or fixed mutations (Stoneking, 2000).

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