Journal of Molecular Evolution

, Volume 48, Issue 4, pp 427–434

Nucleotide Substitution Rate of Mammalian Mitochondrial Genomes

Authors

  • Graziano  Pesole
    • Dipartimento di Fisiologia e Biochimica Generali, Università di Milano, via Celoria 26, 20133 Milano, Italy
  • Carmela  Gissi
    • Dipartimento di Biochimica e Biologia Molecolare, Università di Bari, via Orabona 4, 70125 Bari, Italy
  • Anna  De Chirico
    • Dipartimento di Biochimica e Biologia Molecolare, Università di Bari, via Orabona 4, 70125 Bari, Italy
  • Cecilia  Saccone
    • Dipartimento di Biochimica e Biologia Molecolare, Università di Bari, via Orabona 4, 70125 Bari, Italy

DOI: 10.1007/PL00006487

Cite this article as:
Pesole, G., Gissi, C., De Chirico, A. et al. J Mol Evol (1999) 48: 427. doi:10.1007/PL00006487

Abstract.

We present here for the first time a comprehensive study based on the analysis of closely related organisms to provide an accurate determination of the nucleotide substitution rate in mammalian mitochondrial genomes. This study examines the evolutionary pattern of the different functional mtDNA regions as accurately as possible on the grounds of available data, revealing some important ``genomic laws.'' The main conclusions can be summarized as follows. (1) High intragenomic variability in the evolutionary dynamic of mtDNA was found. The substitution rate is strongly dependent on the region considered, and slow- and fast-evolving regions can be identified. Nonsynonymous sites, the D-loop central domain, and tRNA and rRNA genes evolve much more slowly than synonymous sites and the two peripheral D-loop region domains. The synonymous rate is fairly uniform over the genome, whereas the rate of nonsynonymous sites depends on functional constraints and therefore differs considerably between genes. (2) The commonly accepted statement that mtDNA evolves more rapidly than nuclear DNA is valid only for some regions, thus it should be referred to specific mitochondrial components. In particular, nonsynonymous sites show comparable rates in mitochondrial and nuclear genes; synonymous sites and small rRNA evolve about 20 times more rapidly and tRNAs about 100 times more rapidly in mitochondria than in their nuclear counterpart. (3) A species-specific evolution is particularly evident in the D-loop region. As the divergence times of the organism pairs under consideration are known with sufficient accuracy, absolute nucleotide substitution rates are also provided.

Key words: Nucleotide substitution rate — Mammalia — Mitochondrial DNA — Comparative analysis

Copyright information

© Springer-Verlag New York Inc. 1999