A comparison between petrous bone and tooth, femur and tibia DNA analysis from degraded skeletal remains.

Skeletal remains are the only biological material that remains after long periods; however, environmental conditions such as temperature, humidity, and pH affect DNA preservation, turning skeletal remains into a challenging sample for DNA laboratories. Sample selection is a key factor, and femur and tooth have been traditionally recommended as the best substrate of genetic material. Recently, petrous bone (cochlear area) has been suggested as a better option due to its DNA yield. This research aims to evaluate the efficiency of petrous bone compared to other cranium samples (tooth) and postcranial long bones (femur and tibia). A total amount of 88 samples were selected from 38 different individuals. The samples were extracted by using an organic extraction protocol, DNA quantification by Quantifiler Trio kit and amplified with GlobalFiler kit. Results show that petrous bone outperforms other bone remains in quantification data, yielding 15-30 times more DNA than the others. DNA profile data presented likeness between petrous bone and tooth regarding detected alleles; however, the amount of DNA extracted in petrous bones allowed us to obtain more informative DNA profiles with superior quality. In conclusion, petrous bone or teeth sampling is recommended if DNA typing is going to be performed with environmentally degraded skeletal remains.