Multiplex STR typing of aortic tissues from unidentified cadavers.

The DNA of aortic tissues collected at the autopsies of unidentified 47 cadavers was examined using a multiplex short tandem repeat (STR) typing kit. The causes of death included drowning, burning and brain injury among others. Tissues samples were stored in ethanol before DNA extraction. DNA was extracted from about 25mg of dried tissues using a Q1Amp DNA Mini kit (QIAGEN). STR typing was performed using an AmpFlSTR Identifiler PCR Amplification kit (Applied Biosystems) and GeneMapper ID software v. 3.2 (Applied Biosystems). The amount of recovered DNA ranged from 0.006 to 3.44 microg/mg. Tissue samples were collected at estimated times between 1 day and 2 years after death. We were able to type 46/47 tissue samples (98%) and all 15 STR alleles and the amelogenin gene were detected in 38 cases (81%). Successful typing was completed for most tissue samples taken less than 1 month and up until 3 months after death. As the days after death increased, the numbers of alleles with longer DNA fragment sizes decreased. These results suggest that the DNA from aortic tissues can be accurately typed for multiplex STR and amelogenin until about 1 month after death. We found that aortic tissues are one of the most useful samples for forensic personal identification of unidentified bodies.