title: Molecular characterisation of the nucleic acids recovered from aged forensic samples.
abstract: The molecular composition of the genetic substrate recovered from seven aged forensic samples has been extensively investigated. A simple enzymatic test based on DNAseI incubation of the extracts showed that the UV-fluorescent material from the forensic specimens is composed of nucleic acids, with the DNA fraction representing at least 90% of the total amount. Since spectrophotometric determinations of the extracts showed unreliable results due to anomalous OD(260)/OD(280) ratios, quantification of the nuclease-sensitive genetic material was performed by a slightly modified agarose plate method. The first quantitative data on exogenous contamination in aged forensic samples are provided by slot-blot hybridisation of the extracts to human, bacterial and fungal probes. Only limited amounts of human and contaminant DNA were detected in the samples. The molecular integrity of the primary structure of these aged DNA samples was analysed by reversed-phase HPLC/MS. The data show a good correlation between the degree of chemical damage and the ability to hybridise to molecular probes. The ability to achieve specific genetic profiles was assessed by multiplex PCR amplification of STR loci. Our data show that accurate determination of the molecular composition of the DNA recovered from forensic samples can be extremely useful for a reliable evaluation of the PCR typing results.
authors.affiliation: Department of Legal Medicine and Public Health, University of Pavia, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Previderè
authors.forename: Piero
authors.initials: P
authors.lastname: Micheletti
authors.forename: Romina
authors.initials: R
authors.lastname: Perossa
authors.forename: Pierangela
authors.initials: P
authors.lastname: Grignani
authors.forename: Paolo
authors.initials: P
authors.lastname: Fattorini
mesh_terms: D000367:Age Factors; D000818:Animals; D001426:Bacterial Proteins / Q000032:analysis; D001801:Blood Stains; D001853:Bone Marrow / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000032:analysis*; D004587:Electrophoresis, Agar Gel; D018732:Forensic Anthropology / Q000379:methods*; D005656:Fungal Proteins / Q000032:analysis; D006801:Humans; D013058:Mass Spectrometry; D009132:Muscles / Q000737:chemistry; D009693:Nucleic Acid Hybridization; D016133:Polymerase Chain Reaction / Q000379:methods; D015203:Reproducibility of Results; D040521:Subcutaneous Tissue / Q000737:chemistry; D020080:Tandem Repeat Sequences
chemical_list: D001426:Bacterial Proteins; D005656:Fungal Proteins; D004247:DNA