DNA Chemical Instability


DNA is a relatively unstable molecule that undergoes hydrolytic, oxidative and nonenzymatic degradation. Its instability places limitations on its survival in the geosphere yet enables its rapid repair and turnover in our cells.

Keywords: DNA damage; repair; ancient DNA

Figure 1.

Sites of major forms of DNA damage. Adapted from Lindahl (1993).

Figure 2.

The products of deamination of the four major bases.

Figure 3.

Base adducts formed in DNA as a result of (a) oxidation, (b) alkylation and (c) formation of cyclic addition via a base propenal.

Figure 4.

Schematic representation of the two major repair pathways: (a) base excision repair and (b) nucleotide excision repair.

Figure 5.

Some extinct organisms from which DNA sequences have been determined (bottom left to top right): quagga, marsupial wolf, sabre‐toothed cat, moa, mammoth, cave bear, blue antelope, giant ground sloth, aurochs, mastodon, New Zealand coot, South Island piopio, Steller's sea cow, Neanderthal, Aptornis defossor, Shasta ground sloth, pig‐footed bandicoot, moa‐nalo, Myotragus balearicus. Reproduced with permission from Hofreiter et al. (2001).

Figure 6.

Schematic phylogenetic tree relating the mitochondrial DNAs of modern humans and three Neanderthals from Croatia, Caucasus and Germany. Reproduced with permission from Hofreiter et al. (2001)


Further Reading

Akazawa T, Aoki K and Bar‐Yosef O (eds) (1998) Neandertals and Modern Humans in Western Asia. New York: Plenum Press.

Cooper A and Poinar HN (2000) Ancient DNA: do it right or not at all. Science 289: 1139.

Dizdaroglu M (1992) Oxidative damage to DNA in mammalian chromatin. Mutation Research 275: 331–342.

Friedberg EC, Walker GC and Siede W (1995) DNA Repair and Mutagenesis. Washington, DC: ASM Press.

Hofreiter M, Poinar HN, Spaulding GS et al. (2000) A molecular analysis of ground sloth diet through the last glaciation. Molecular Ecology 9: 1975–1984.

Hofreiter M, Serre D, Poinar NH, Kuch M and Pääbo S (2001) Ancient DNA. Nature Genetics Reviews 2: 353–359.

Höss M, Jaruga P, Zastawny TH, Dizdaroglu M and Pääbo S (1996) DNA damage and DNA sequence retrieval from ancient tissues. Nucleic Acids Research 24: 1304–1307.

Lindahl T (1993) Instability and decay in the primary structure of DNA. Nature 362: 709–715.

Poinar HN, Hofreiter M, Spaulding GS et al. (1998) Molecular coproscopy: dung and diet of the extinct ground sloth Nothrotheriops shastensis. Science 281: 402–406.

Poinar HN, Kuch M, Sobolik K et al. (2001) A molecular analysis of the dietary diversity of three Archaic Native Americans. Proceedings of the National Academy of Sciences of the USA 98: 4317–4322.

Shapiro R (1981) Damage to DNA caused by hydrolysis. In: Seeberg E and Kleppe K (eds) Chromosome Damage and Repair. New York: Plenum Press.

Tattersal L (2000) The Last Neandertal. New York: Westview Press, Neuraumont Publishing Company.

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How to Cite close
Poinar, Hendrik(Mar 2002) DNA Chemical Instability. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0000838]