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Age estimation from trace sources

Provision of a ‘biological witness’ to a crime is currently the focus of much forensic genetics research involving information on visible characteristics and ancestry, and provision of a reliable prediction of age of the donor of a crime stain is a useful addition to this. The research exploits epigenetic changes, such as additions or loss of methyl groups to cytosine nucleotides that are associated with age. The extent of methylation is quantified by converting non-methylated cytosines to uracil through bisulphite treatment and their subsequent conversion to thymine when amplified, assessing the ratio of the two nucleotides in target areas. Because forensic material is limited the research must identify and model a small number that are highly correlated with age yet not affected by differences in tissue origin, sex, origin and disease to provide a prediction of chronological age with minimal error.

To date this research has focused on accurate age prediction of all ages from trace blood spots. Current methods predict an average error of 3.3 years, reducing to 2.6 years in people under 55 years of age. There is an increasing interest in being able to accurately determine whether an individual is an adult or a child. Current assessment of age relies on holistic assessment to indicate whether or not the physical appearance and demeanour of an individual strongly suggests they are significantly over 18, but applicability and potential bias when applied to a group of asylum seekers has led to doubts about the reliability of this approach, particularly where presenting individuals are not European. While measurements of bones and teeth through the use of X-rays can be useful, our future research will focus on developing markers from a non-invasive source, such as buccal swabs, and limited to a range of around ten to twenty-five years of age.

Aims

Development of a methylation panel to provide a robust differentiation of adults and children in a global population.

Methods

Selection of CpG markers sensitive to age differences in adolescents and young adults within buccal swabs.

Summary of Findings

We are able to estimate age from trace samples with average error in forensic blood stains around 3.3 years.

Conferences

  • Crossing Forensic Borders, April 2021, ‘Developing an epigenetics-based tool for the inference of chronological age from blood traces’.
  • 28th Congress of the International Society for Forensic Genetics September 2019 Prague, The Czech Republic. A coming of age tale
  • MiSeq FGx Forensic Genomics System Workshop August 2019 London UK. ‘Developing new forensic intelligence tools: From crime scene stains to chronological age’
  • King’s Forensics 1st Inaugural Symposium September 2019 London UK. ‘DNA methylation-based age prediction: A coming of age tale’
  • German DNA Profiling Group (GEDNAP) Spurenworkshop February 2018 Basel Switzerland. ‘Developing new forensic intelligence tools: From crime scene stains to chronological age’
  • Congress of the International Society for Forensic Genetics August 2017 Seoul S. Korea. ‘Correlating DNA methylation data with chronological age: A quest for the optimal statistical model’
  • 17th European Forensic DNA Working Group Meeting April 2016 Florence Italy. ‘Investigating the sensitivity of a DNA methylation-based age prediction method’
  • The Chartered Society of Forensic Sciences Postgraduate Research Symposium November 2015 Manchester UK ‘Development of a massively parallel sequencing method for the quantification of DNA methylation in age prediction’

Media coverage

Conferences

  • Crossing Forensic Borders, April 2021, ‘Developing an epigenetics-based tool for the inference of chronological age from blood traces’.
  • 28th Congress of the International Society for Forensic Genetics September 2019 Prague, The Czech Republic. A coming of age tale
  • MiSeq FGx Forensic Genomics System Workshop August 2019 London UK. ‘Developing new forensic intelligence tools: From crime scene stains to chronological age’
  • King’s Forensics 1st Inaugural Symposium September 2019 London UK. ‘DNA methylation-based age prediction: A coming of age tale’
  • German DNA Profiling Group (GEDNAP) Spurenworkshop February 2018 Basel Switzerland. ‘Developing new forensic intelligence tools: From crime scene stains to chronological age’
  • Congress of the International Society for Forensic Genetics August 2017 Seoul S. Korea. ‘Correlating DNA methylation data with chronological age: A quest for the optimal statistical model’
  • 17th European Forensic DNA Working Group Meeting April 2016 Florence Italy. ‘Investigating the sensitivity of a DNA methylation-based age prediction method’
  • The Chartered Society of Forensic Sciences Postgraduate Research Symposium November 2015 Manchester UK ‘Development of a massively parallel sequencing method for the quantification of DNA methylation in age prediction’

Media coverage

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