Male DNA under female fingernails after scratching: transfer and persistence evaluation by RT-PCR analysis and Y-STR typing

  • Alessandra Iuvaro
  • Carla Bini
  • Silvia Dilloo
  • Stefania Sarno
  • Susi Pelotti
Original Article


The collection of biological debris beneath fingernails can be useful in forensic casework when a struggle between the victim and the offender is suspected. In the present study, we set up a controlled scratching experiment in which female volunteers scratched the male volunteers’ forearms, simulating a defensive action during an assault. A total of 160 fingernail samples were collected: 80 “control samples” before the scratching, 40 samples immediately after the scratching (t = 0 h), and 40 samples 5 h after the scratching (t = 5 h). The aim was to evaluate, using a real-time PCR approach and Y-STR profiling, the transfer and the persistence of male DNA under female fingernails after scratching. A significant reduction in DNA yield was observed between fingernail samples collected immediately and those collected 5 h after scratching, with a corresponding decrease in Y-STR profile quality. Overall, 38/40 (95%) of the fingernail samples collected immediately (t = 0 h) and 24/40 (60%) of those collected 5 h later (t = 5 h) were suitable for comparison and the scratched male volunteers could not be excluded as donors of the foreign DNA from 37 (92.5%) of the t = 0 h and from 10 (25%) of the t = 5 h profiles. The analysis of male DNA under female fingernails showed that Y-chromosome STR typing may provide extremely valuable genetic information of the male contributor(s), although 5 h after scratching the profile of the scratched male was lost in three-quarters of samples.


Scratching experiment Fingernail debris Y-STR typing RT-PCR Male/female mixtures 



The authors would like to thank all volunteers who participated to the scratching study.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Statement of human rights

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.

Statement on the welfare of animals

This article does not contain any ties with animals performed by any of the authors.

Informed consent

Informed consent was obtained from all individual participants included in this study with the ethical approval of the Bioethical Committee of the University of Bologna, Italy.

Supplementary material

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Supplementary Table 1 (DOCX 15 kb)


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Medical and Surgical Sciences (DIMEC)University of Bologna (Unibo), Unit of Legal MedicineBolognaItaly
  2. 2.Laboratory of Molecular Anthropology, Department of Biological, Geological and Environmental Sciences (BiGeA)University of Bologna (Unibo)BolognaItaly

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