Mixed stains from sexual assault cases: autosomal or Y-chromosome short tandem repeats?
We analyzed forensic DNA samples from four cases of sexual assault, using the Y-chromosome-specific human DNA markers and a panel of autosomal short tandem repeats (STRs). The presence of male contribution was evaluated by the analysis of the Amelogenin locus. A panel of tetrameric Y-STR (DYS19, DYS390, DYS391, DYS392, DYS385, DYS389I and II) was used in further analysis of samples, increasing the efficiency of the forensic genetic analyses. It was possible to identify a partial or full Y-profile of the rapists in different DNA mixtures when genetic profile could not be detected by autosomal STRs. However, in the case of male/male DNA mixture, only the victim's Y-profile could be obtained because the DNA of the offenders was present in low amounts. When the mixture contained different male/male proportion of DNA, only the full profile of the major component could be detected. In cases where male/female DNA mixed stains contained a sufficient amount of male DNA, the analysis of autosomal STRs was adequate enough to identify the full profile of the rapist. Our experience shows that the main advantage of the Y-STR approach is its ability to detect the male component in the mixed stains when the DNA of the male contributor is present only in a very small amount.
Cerri
Nicoletta
N
Institute of Forensic Medicine, University of Brescia, Italy.
Ricci
Ugo
U
Sani
Ilaria
I
Verzeletti
Andrea
A
De Ferrari
Francesco
F
D053523:Amelogenin; D041322:Chromosomes, Human, Y / Q000235:genetics*; D016172:DNA Fingerprinting / Q000379:methods*; D003746:Dental Enamel Proteins / Q000235:genetics; D005260:Female; D005554:Forensic Medicine / Q000379:methods*; D006801:Humans; D008297:Male; D011902:Rape; D020080:Tandem Repeat Sequences
D053523:Amelogenin; D003746:Dental Enamel Proteins