Sex identification of old skeletal remains by DNA analysis: the report of three cases.

We analyzed the DNA in the remains of three skeletons affected by severe post-mortem modification to identify the sex of the cases. We analyzed DNA extracted from bone, bone marrow and a tooth by Southern blot hybridization with Y chromosome specific probe and PCR to amplify the sex chromosome specific sequence. The first case had been preserved underground in a deep grave for two months, the second case was found in a forest after more than five years, and the last case had been kept in a styrofoam box for few years. The detective sensitivity of Southern hybridization improved to nearly the same level as PCR with the aid of computed image processing. Although PCR was of obvious benefit when analyzing small amounts of biological evidence, amplification was impossible in case the target sequence became lost or changed. As a result, we identify the sexes of the three cases by Southern blot hybridization or PCR using bone, bone marrow and tooth DNA. The old skeletal remains were suitable for sex identification in spite of severe post-mortem change, due to preservation in a condition protected from external influences.