Bone age

In mass disasters and in many homicides the identification of the victims is an important, but challenging task. Countries around the world participate in collaborative networks to provide reference information of missing persons to facilitate the identification casework. However, when there is no clue as to the identity of the victim, the sex and the age constitute the most important variables to limit the search for possible matches. The sex can usually be determined by either anthropological methods or with DNA analyses, whereas the age of the person remains a challenge to all professionals. We have developed a feasible protocol for analysis of bomb-pulse generated C-14 levels in dental enamel of teeth, which can provide an estimate of the year of birth with high accuracy. These analyses are now performed on a regular basis upon the request by pathologists and the police. By adding the age at death of the person, as estimated e.g. by aspartic acid racemization analysis, the approximate year of death can also be determined. Analysis of C-13 can be performed in parallel and provide clues to the geographical origin of the decedent. We have now started to perform studies on human bones, since many skeletal finds lack teeth. The analyses include bomb-pulse generated C-14, and aspartic acid racemization ratio in different fractions of select types of bones, and also DNA methylation of select genes. Since different components of bone are exchanged at different rates during life, we will apply mathematical modeling to provide appropriate prediction of year of birth and age at death, respectively. The plan is also to analyze a few more stable isotopes to improve prediction of provenance and hopefully we will be able to track migration of subjects.

PI: Kanar Alkass. kanar.alkass@ki.se