Protein Chemistry

The Rag-and-Bone Trade

See allHide authors and affiliations

Science  14 Aug 2009:
Vol. 325, Issue 5942, pp. 794
DOI: 10.1126/science.325_794c

Sequencing ancient DNA can establish genetic differences among species and can document population changes over long periods, yet a major challenge is to avoid extensive sampling of rare and ancient specimens. One technique used to probe for the presence of well-preserved DNA in such specimens is to measure the extent of racemization of aspartic acid. Shapiro et al. have performed replicate amino acid analysis in three laboratories of 91 samples of human and animal bones that had been recovered from a range of burial environments and ages. They found no correlation between racemization and the successful amplification of ancient DNA. Collagen, which constitutes up to 95% of bone protein, contributes most of the aspartic acid in bone, but racemization is slowed by its triple helical structure; after denaturation into soluble gelatin, racemization proceeds readily, but gelatin is more easily lost in the burial environment.

Proc. R. Soc. B 276, 2971 (2009).

Navigate This Article