Pregledni rad
Estimating the number of contributors to two-, three-, and four-person mixtures containing DNA in high template and low template amounts
Jaheida Perez
; Office of Chief Medical Examiner of the City of New York, The Department of Forensic Biology, New York, NY, USA
Adele A. Mitchell
; Office of Chief Medical Examiner of the City of New York, The Department of Forensic Biology, New York, NY, USA
Nubia Ducasse
; Office of Chief Medical Examiner of the City of New York, The Department of Forensic Biology, New York, NY, USA
Jeannie Tamariz
; Office of Chief Medical Examiner of the City of New York, The Department of Forensic Biology, New York, NY, USA
Theresa Caragine
; Office of Chief Medical Examiner of the City of New York, The Department of Forensic Biology, New York, NY, USA
Sažetak
Aim To develop guidelines to estimate the number of contributors
to two-, three-, and four-person mixtures containing
either high template DNA (HT-DNA) or low template
DNA (LT-DNA) amounts.
Methods Seven hundred and twenty-eight purposeful
two-, three-, and four-person mixtures composed of 85
individuals of various ethnicities with template amounts
ranging from 10 to 500 pg were examined. The number
of alleles labeled at each locus and the number of labeled
different and repeating alleles at each locus as well over all
loci for 2 HT-DNA or 3 LT-DNA replicates were determined.
Guidelines based on these data were then evaluated with
117 mixtures generated from items handled by known individuals.
Results The number of different alleles over all loci and
replicates was used to initially categorize mixtures. Ranges
were established based on the averages plus and minus
2 standard deviations, and to encompass all observations,
the maximum and the minimum values. To differentiate
samples that could be classified in more than one grouping,
the number of loci with 4 or more repeating or different
alleles, which were specific to three- and four-person
mixtures, were verified. Misclassified samples showed an
extraordinary amount of allele sharing or stutter.
Conclusions These guidelines proved to be useful tools to
distinguish low template and high template two-, three-,
and four-person mixtures. Due to the inherent higher
probability of allele sharing, four-person mixtures were
more challenging. Because of allelic drop-out, this was also
the case for samples with very low amounts of template
DNA or extreme mixture ratios.
Ključne riječi
Hrčak ID:
71441
URI
Datum izdavanja:
15.6.2011.
Posjeta: 1.290 *