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Post mortem DNA degradation of human tissue experimentally mummified in salt.

Shved N, Haas C, Papageorgopoulou C, Akguel G, Paulsen K, Bouwman A, Warinner C, Rühli F - PLoS ONE (2014)

Bottom Line: Mummified human tissues are of great interest in forensics and biomolecular archaeology.Skin and skeletal muscle were sampled at multiple time points over a period of 322 days and subjected to genetic analysis.The study outcome reveals a very good level of DNA preservation in salt mummified tissues over the course of the experiment, with an overall slower rate of DNA fragmentation in skin compared to muscle.

View Article: PubMed Central - PubMed

Affiliation: Institute of Evolutionary Medicine, University of Zurich, Zurich, Switzerland.

ABSTRACT
Mummified human tissues are of great interest in forensics and biomolecular archaeology. The aim of this study was to analyse post mortem DNA alterations in soft tissues in order to improve our knowledge of the patterns of DNA degradation that occur during salt mummification. In this study, the lower limb of a female human donor was amputated within 24 h post mortem and mummified using a process designed to simulate the salt dehydration phase of natural or artificial mummification. Skin and skeletal muscle were sampled at multiple time points over a period of 322 days and subjected to genetic analysis. Patterns of genomic fragmentation, miscoding lesions, and overall DNA degradation in both nuclear and mitochondrial DNA was assessed by different methods: gel electrophoresis, multiplex comparative autosomal STR length amplification, cloning and sequence analysis, and PCR amplification of different fragment sizes using a damage sensitive recombinant polymerase. The study outcome reveals a very good level of DNA preservation in salt mummified tissues over the course of the experiment, with an overall slower rate of DNA fragmentation in skin compared to muscle.

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The change of the peak height ratio of the shorter D19 locus (sum of the peak heights of alleles 13 and 14) relative to the longer D18 locus (peak height of homozygous allele 15) within the DNA profiles of muscle and skin samples during the 322 days of salt desiccation.For both tissues, the line of best fit for the change in the peak height ratio through time is logarithmic, with lower ratios observed for skin.
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pone-0110753-g003: The change of the peak height ratio of the shorter D19 locus (sum of the peak heights of alleles 13 and 14) relative to the longer D18 locus (peak height of homozygous allele 15) within the DNA profiles of muscle and skin samples during the 322 days of salt desiccation.For both tissues, the line of best fit for the change in the peak height ratio through time is logarithmic, with lower ratios observed for skin.

Mentions: In the multiplex STR assay, signal intensity is proportional to the quantity of DNA containing the targeted marker. In fresh tissue, the quantity of DNA should be equal for all markers, but in highly degraded tissues, DNA fragmentation results in an underrepresentation of longer markers. In order to compare the relative proportion of short to long targets, a ratio was calculated for the shorter locus D19S433 (amplicon range 102–135 bp) and the longer locus D18S51 (amplicon range 262–355 bp) (Figure 3) [42]. A ratio of 1 indicates no DNA size bias in the extract. A ratio greater than 1 indicates an excess of short targets in the DNA extract, likely caused by the loss of longer DNA targets through fragmentation. At day 0 of the artificial mummification experiment the ratio is approximately 1, but this value increases to over 2 for both skin and muscle tissue by day 322.


Post mortem DNA degradation of human tissue experimentally mummified in salt.

Shved N, Haas C, Papageorgopoulou C, Akguel G, Paulsen K, Bouwman A, Warinner C, Rühli F - PLoS ONE (2014)

The change of the peak height ratio of the shorter D19 locus (sum of the peak heights of alleles 13 and 14) relative to the longer D18 locus (peak height of homozygous allele 15) within the DNA profiles of muscle and skin samples during the 322 days of salt desiccation.For both tissues, the line of best fit for the change in the peak height ratio through time is logarithmic, with lower ratios observed for skin.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4206501&req=5

pone-0110753-g003: The change of the peak height ratio of the shorter D19 locus (sum of the peak heights of alleles 13 and 14) relative to the longer D18 locus (peak height of homozygous allele 15) within the DNA profiles of muscle and skin samples during the 322 days of salt desiccation.For both tissues, the line of best fit for the change in the peak height ratio through time is logarithmic, with lower ratios observed for skin.
Mentions: In the multiplex STR assay, signal intensity is proportional to the quantity of DNA containing the targeted marker. In fresh tissue, the quantity of DNA should be equal for all markers, but in highly degraded tissues, DNA fragmentation results in an underrepresentation of longer markers. In order to compare the relative proportion of short to long targets, a ratio was calculated for the shorter locus D19S433 (amplicon range 102–135 bp) and the longer locus D18S51 (amplicon range 262–355 bp) (Figure 3) [42]. A ratio of 1 indicates no DNA size bias in the extract. A ratio greater than 1 indicates an excess of short targets in the DNA extract, likely caused by the loss of longer DNA targets through fragmentation. At day 0 of the artificial mummification experiment the ratio is approximately 1, but this value increases to over 2 for both skin and muscle tissue by day 322.

Bottom Line: Mummified human tissues are of great interest in forensics and biomolecular archaeology.Skin and skeletal muscle were sampled at multiple time points over a period of 322 days and subjected to genetic analysis.The study outcome reveals a very good level of DNA preservation in salt mummified tissues over the course of the experiment, with an overall slower rate of DNA fragmentation in skin compared to muscle.

View Article: PubMed Central - PubMed

Affiliation: Institute of Evolutionary Medicine, University of Zurich, Zurich, Switzerland.

ABSTRACT
Mummified human tissues are of great interest in forensics and biomolecular archaeology. The aim of this study was to analyse post mortem DNA alterations in soft tissues in order to improve our knowledge of the patterns of DNA degradation that occur during salt mummification. In this study, the lower limb of a female human donor was amputated within 24 h post mortem and mummified using a process designed to simulate the salt dehydration phase of natural or artificial mummification. Skin and skeletal muscle were sampled at multiple time points over a period of 322 days and subjected to genetic analysis. Patterns of genomic fragmentation, miscoding lesions, and overall DNA degradation in both nuclear and mitochondrial DNA was assessed by different methods: gel electrophoresis, multiplex comparative autosomal STR length amplification, cloning and sequence analysis, and PCR amplification of different fragment sizes using a damage sensitive recombinant polymerase. The study outcome reveals a very good level of DNA preservation in salt mummified tissues over the course of the experiment, with an overall slower rate of DNA fragmentation in skin compared to muscle.

Show MeSH
Related in: MedlinePlus