A Lawrence Livermore National Laboratory researcher and a team of international collaborators have discovered a multidisciplinary approach to identifying the remains of missing persons.
Using "bomb pulse" radiocarbon analysis with recently developed anthropological analysis and forensic DNA techniques, the researchers were able to identify the remains of a missing child 41 years after the discovery of the body.
In 1968, a child's cranium was recovered from the banks of a northern Canadian river. Initial analysis concluded that the cranium came from the body of a 7-to-9-year-old child and no identity could be determined. The case went cold and was reopened later.
Recently, the remains underwent reanalysis at Simon Fraser University in Canada, where skull measurements, skeletal ossification and dental formation indicated that the child died at approximate 4 and 1/2-years old. At Lawrence Livermore, researchers used radiocarbon analysis on enamel from two teeth to find a more precise birth date.
Age determination in John/Jane Doe cases is important in the setting of a crime investigation or a mass disaster because it can guide investigators to the correct identity among a large number of possible matches, a release stated.
SFU's forensic DNA analysis also indicated that the child was a male and the obtained mitochondrial profile that matched a living maternal relative to the presumed missing child.
Lawrence Livermore and SFU's multidisciplinary analyses highlight the enormous potential of combining these methods, the release continued. Researchers expect possible identifications in forensic cold cases dating to within the last 60 years.
"There are thousands of John Doe and Jane Doe cold cases in the United States," said Livermore scientist Bruce Buchholz, who conducted the radiocarbon analysis. "I believe we could provide birthdates and death dates for many of these cases."
Nuclear weapons testing during the Cold War caused a surge in global levels of carbon-14, which was carefully recorded over time and remains in the dental enamel. Scientists can use the radiocarbon technique to relate the extensive atmospheric record for carbon-14 to when the tooth was formed and calculate the age of the tooth and its owner.
At the laboratory's Center for Accelerator Mass Spectrometry, Buchholz was able to determine the child's birth date within one to two years. In the missing child case, the average of the crown's enamel formation span occurred between 1959 and 1961.
"In a conservative estimate, the carbon-14 value for the crown's enamel would correspond with a birth year between 1958 and 1962," Buchholz said.
The carbon-14 dates, combined with the age-at-death estimate using anthropological techniques, suggest that the child was born between 1958 and 1962 and died between 1963 and 1968.
The multi-national research also has implications for the identities of victims in mass graves or mass fatality contexts, where a combined DNA and radiocarbon analysis may distinguish between maternal relations.
Several other institutions participated in the research, including the Karolinska Institute in Sweden and the British Columbia Institute of Technology. Findings appeared in the September issue of the "Journal of Forensic Sciences."