Highlights
- •A pilot study looking at sexual assault cases where no spermatozoa were present was performed using the PowerPlex® Y23 system.
- •Samples with a large excess of female DNA present generated artefact peaks; these are mentioned within the PowerPlex® Y23 system, technical manual.
- •Artefact peaks that fall within allelic positions have the potential to be mistaken for allelic peaks.
- •Characterisation of the artefact peaks has been performed.
Abstract
Male on female sexual assault cases that involve azoospermic individuals, those where
the male has penetrated but failed to ejaculate, those where there has been an extended
interval between the sexual assault and sample collection or where there has been
only digital penetration are often difficult to investigate by employing traditional
autosomal STR testing. Such cases often involve minimal amounts of male DNA either
being deposited initially or remaining after the passage of time. These cases are
often further complicated by the presence of large amounts of female DNA compared
to the relatively small amounts of male DNA on the intimate samples taken. Y-STR kits
provide a solution that allows targeting of male DNA in a mixed male/female sample.
However, large quantities of excess female DNA have the potential to generate non-specific
artefact peaks. Here we characterise a number of previously reported artefacts observed
in the PowerPlex® Y23 system. We demonstrate that some of these artefacts can impact on profile interpretation
and that they are highly dependent on the levels of female DNA present. These artefacts
have been characterised to assist practitioners with the interpretation of such samples.
Keywords
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Article info
Publication history
Published online: May 19, 2016
Accepted:
May 14,
2016
Received in revised form:
May 6,
2016
Received:
December 21,
2015
Identification
Copyright
© 2016 Elsevier Ireland Ltd. All rights reserved.
