Reliable genetic identification of burnt human remains

The identification of severely burnt human remains by genetic fingerprinting is a common task in forensic routine work. In cases of extreme fire impact, only hard tissues (bones, teeth) may be left for DNA analysis. DNA extracted from burnt bone fragments may be highly degraded, making an amplification of genetic markers difficult or even impossible. Furthermore, heavily burnt bones are very prone to contamination with external DNA. We investigated whether authentic DNA profiles can be generated from human bones showing different stages of fire induced destruction (well preserved, semi-burnt, black burnt, blue-grey burnt, blue-grey-white burnt). DNA was extracted from 71 bone fragments derived from 13 individuals. Obtained genetic patterns (STRs and mtDNA sequences) were compared to the genetic pattern of the respective bodies. Our results show that the identification via DNA analysis is reliably and reproducibly possible from well preserved and semi-burnt bones. In black burnt bones the DNA was highly degraded and in some cases no nuclear DNA was left, leaving mitochondrial DNA analysis as an option. Blue-grey burnt bones lead only sporadically to authentic profiles. The investigation of blue-grey-white burnt bones barely led to reliable results.