Using Isotopes to Tell the Stories of the Unidentified
According to the National Missing and Unidentified Persons System (NamUs), 600,000 individuals go missing in the United States each year. While many are quickly found, it is estimated that 4,400 unidentified bodies are recovered each year, with 1,000 of them remaining unidentified after one year. All told, there are currently more than 40,000 sets of human remains listed as unidentified in the United States. While advances in DNA technology have assisted in providing identities for many, limitations remain, especially with populations that are non-native to the United States. Many who have perished while attempting to migrate from Latin American countries have no genetic relatives in the United States, and they are undocumented. Those who may be relatives are hesitant to come forward to submit DNA, because they are also undocumented. Without reference samples to use for comparison, the power of DNA is limited. In cases where medical examiners are limited by the information that DNA analysis can provide, forensic anthropologists may be able to shed some light. As specialists in the hard tissues of the body, such as teeth, bones, fingernails, and even hair, forensic anthropologists tell the story of the deceased by providing a biological profile. This profile includes the sex, age, ancestry, living stature at the time of death, and a rough post-mortem interval. They are also able to determine if trauma or disease was present. In this video, Dr. Chelsey Juarez of Fresno State describes how specially trained forensic anthropologists are able to perform an isotopic analysis to help determine where a person may have lived.