Mitochondrial DNA sequences of primates: tempo and mode of evolution
Abstract
We cloned and sequenced a segment of mitochondrial DNA from human, chimpanzee, gorilla, orangutan, and gibbon. This segment is 896 bp in length, contains the genes for three transfer RNAs and parts of two proteins, and is homologous in all 5 primates. The 5 sequences differ from one another by base substitutions at 283 positions and by a deletion of one base pair. The sequence differences range from 9 to 19% among species, in agreement with estimates from cleavage map comparisons, thus confirming that the rate of mtDNA evolution in primates is 5 to 10 times higher than in nuclear DNA. The most striking new finding to emerge from these comparisons is that transitions greatly outnumber transversions. Ninety-two percent of the differences among the most closely related species (human, chimpanzee, and gorilla) are transitions. For pairs of species with longer divergence times, the observed percentage of transitions falls until, in the case of comparisons between primates and non-primates, it reaches a value of 45. The time dependence is probably due to obliteration of the record of transitions by multiple substitutions at the same nucleotide site. This finding illustrates the importance of choosing closely related species for analysis of evolutionary process. The remarkable bias toward transitions in mtDNA evolution necessitates the revision of equations that correct for multiple substitutions at the same site. With revised equations, we calculated the incidence of silent and replacement substitutions in the two protein-coding genes. The silent substitution rate is 4 to 6 times higher than the replacement rate, indicating strong functional constraints at replacement sites. Moreover, the silent rate for these two genes is about 10% per million years, a value 10 times higher than the silent rate for the nuclear genes studied so far. In addition, the mean substitution rate in the three mitochondrial tRNA genes is at least 100 times higher than in nuclear tRNA genes. Finally, genealogical analysis of the sequence differences supports the view that the human lineage branched off only slightly before the gorilla and chimpanzee lineages diverged and strengthens the hypothesis that humans are more related to gorillas and chimpanzees than is the orangutan.
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Early reports comparing nucleotide substitutions in mtDNA from somatic tissues of different primates revealed a 10-fold higher rate of evolution for mtDNA relative to the nuclear genome.
“Early reports comparing nucleotide substitutions in mtDNA from somatic tissues of different primates revealed a 10-fold higher rate of evolution for mtDNA relative to the nuclear genome (Brown et al., 1979; Brown et al., 1982), implying a relatively high mutation rate for mtDNA.”
From Role of the mitochondrial DNA replication machinery in mitochondrial DNA mutagenesis, aging and age-related diseases (2017) · cites this paper as Brown et al., 1982
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- Authors
- Brown, W. M., Prager, E. M., Wang, A., & Wilson, A. C.
- Affiliations
- University of California, Berkeley (US)
- Venue
- Journal of Molecular Evolution
- Published
- 1982-07
- Volume
- 18
- Issue
- 4
- Pages
- 225-239
- ISSN
- 0022-2844 (ISSN-L)
- 1432-1432
- OpenAlex
- W2037764264
- Cited by
- 1,554
- References
- 62
- Citations by year
- 2026: 9 · 2025: 10 · 2024: 14 · 2023: 19 · 2022: 51 · 2021: 17 · 2020: 16 · 2019: 17 · 2018: 12 · 2017: 16 · 2016: 24 · 2015: 28 · 2014: 47 · 2013: 33 · 2012: 29
- FWCI
- 17.68
- Type
- journal article
- Language
- en
- Open access
- closed
- Licence
- www.springer.com/tdm (tdm)
- Locations
- Journal of Molecular Evolution (publishedVersion)
- PubMed (publishedVersion)
- Deep Blue (University of Michigan) (acceptedVersion)
- Topics
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Genomics and Phylogenetic Studies
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Genetic diversity and population structure
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Evolution and Genetic Dynamics
- Keywords
- mitochondrial DNA, primate evolution, substitution rate, multiple substitutions, tRNA genes, human-chimpanzee divergence, orangutans, gibbons, molecular clock, genealogy
- MeSH terms
- Animals, Base Sequence, Pan troglodytes, Cloning, Molecular, DNA Restriction Enzymes, DNA, Mitochondrial, Biological Evolution, Gorilla gorilla, Humans, Hylobates, Plasmids, Pongo pygmaeus, Primates, RNA, Transfer
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