The impact of random natural variability on aspartic acid racemization ratios in enamel from different types of human teeth

TY - JOUR

T1 - The impact of random natural variability on aspartic acid racemization ratios in enamel from different types of human teeth

AU - Griffin, R. C.

AU - Penkman, K. E.H.

AU - Moody, H.

AU - Collins, M. J.

PY - 2010/7/1

Y1 - 2010/7/1

N2 - Previous research has indicated that the extent of amino acid racemization in enamel varies systematically between tooth types within the dentition. This phenomenon was suggested to be due to differences in temperature at various locations within the mouth. This paper presents an analysis of aspartic acid racemization in a fraction of the enamel proteins which should be particularly susceptible to deviations in temperature, in order to assess the impact of temperature on variability in racemization values. The acid soluble fraction of the enamel was analysed from 129 human teeth of different tooth types and from both living individuals and archaeological skeletal remains. Samples were collected by acid etching of the enamel to isolate proteins located a small distance below the enamel surface. For each population, the racemization values for different tooth types were compared to identify any possible systematic variation. Where multiple teeth were analysed from the one individual, the age estimates produced for the different teeth were compared to obtain an indication of the overall level of variability in racemization values. No systematic variation in the extent of racemization between different tooth types was observed in any of the populations analysed. There appeared instead to be a high level of random variability in the extent of racemization, with substantial differences observed between age estimates produced from multiple teeth from the one individual.The results of this study suggest that the differences in racemization values observed here are due to random variations and not the temperature at different locations within the mouth.

AB - Previous research has indicated that the extent of amino acid racemization in enamel varies systematically between tooth types within the dentition. This phenomenon was suggested to be due to differences in temperature at various locations within the mouth. This paper presents an analysis of aspartic acid racemization in a fraction of the enamel proteins which should be particularly susceptible to deviations in temperature, in order to assess the impact of temperature on variability in racemization values. The acid soluble fraction of the enamel was analysed from 129 human teeth of different tooth types and from both living individuals and archaeological skeletal remains. Samples were collected by acid etching of the enamel to isolate proteins located a small distance below the enamel surface. For each population, the racemization values for different tooth types were compared to identify any possible systematic variation. Where multiple teeth were analysed from the one individual, the age estimates produced for the different teeth were compared to obtain an indication of the overall level of variability in racemization values. No systematic variation in the extent of racemization between different tooth types was observed in any of the populations analysed. There appeared instead to be a high level of random variability in the extent of racemization, with substantial differences observed between age estimates produced from multiple teeth from the one individual.The results of this study suggest that the differences in racemization values observed here are due to random variations and not the temperature at different locations within the mouth.

KW - Age at death estimation

KW - Aspartic acid racemization

KW - Enamel

KW - Intra-individual differences

KW - Tooth type

KW - Variability

UR - http://www.scopus.com/inward/record.url?scp=77953916107&partnerID=8YFLogxK

U2 - 10.1016/j.forsciint.2010.04.005

DO - 10.1016/j.forsciint.2010.04.005

M3 - Journal article

C2 - 20462713

AN - SCOPUS:77953916107

SN - 0379-0738

VL - 200

SP - 148

EP - 152

JO - Forensic Science International

JF - Forensic Science International

IS - 1-3

ER -