The effect of temperature on sex determination using DNA-PCR analysis of dental pulp

Forensic applications often necessitate the identification of human remains. This is made more difficult when the tissues have been exposed to high temperatures. Previously, metrical and non-metrical assessments of skeletal remains have been used to assess gender. Recent advances in molecular biology allow amplification of DNA from human blood, dental pulp and other tissues using the polymerase chain reaction (PCR), thus facilitating gender identification. The aim of this study was to investigate the efficacy of utilising DNA retrieved from the pulp of human teeth that had been exposed to different temperatures for different lengths of time, in order to assess gender. DNA was obtained from 94 teeth, 88 of which were isolated (44 male and 44 female), and six male teeth embedded in bone and soft tissue. A 106 base pair fragment from the X chromosome and a 112 base pair fragment from the Y chromosome was amplified from the amelogenin gene. PCR was shown to be 100% reliable when used to assess the gender of teeth which had been heated at 100 degrees C for 15 minutes but less reliable when the teeth were heated at higher temperatures for longer periods of time. Teeth encased in bone and soft tissue yielded better results when subjected to higher temperatures than did the isolated teeth.