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Currently, these techniques are used to estimate the age of fossils, determine the life span of bowhead whales, and detect evidence of extraterrestrial life.
Chemical Whale Tales Since 1981, whale hunters in Alaska have found at least six harpoon heads in bowhead whales that they have killed in the Beaufort Sea, southwest of the Arctic Ocean. Anthropologists at the Smithsonian Institution (Washington, DC) estimate that they are between 130 and 200 years old and were probably used by Inupiat hunters in the late 1700s.
However, in samples from burial sites (19th and 16th century and Neolithic samples from Syria), it was impossible to establish age at death.
We assume that taphonomic processes (time and geochemistry) greatly contribute to the denaturation of the collagen triple helix and higher order structures, thereby allowing the racemization of peptide-bound aspartic acid.
Jurassic Racemization In addition to studying animal life span, Bada also applied racemization analysis to the search for genetic material in ancient fossil and tissue samples.
DNA stability is a major complication in the analysis of ancient genetic material.
Racemization is the process in which one enantiomer of a compound, such as an L-amino acid, converts to the other enantiomer.
The relative proportions of each enantiomer were measured using fluorescence detection.
By conducting aspartic acid racemization measurements using an HPLC/fluorescence detection method, Bada analyzed the bowheads eye lenses to estimate the whales age at the time of death (2).
The eye lens of a bowhead whale is made up of dozens of layers of protein, much like an onion.
The longer the racemization process continues, the closer to 1 the ratio between the D- and L-forms becomes.
This ratio allows chemists to approximate a birth date of a bowhead whale by estimating how long it has been since the first layer in the eye lens formed.
(See box, Pasteurs Racemic Revelation.) In a laboratory setting, scientists are able to measure the degree of racemization using polarimetry, liquid chromatography, capillary electrophoresis, and mass spectrometry.