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Identification of Individuals in a DNA Mixture Using SNP Markers

Received: 9 April 2017     Accepted: 24 April 2017     Published: 10 July 2017
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Abstract

This article focuses mainly on DNA mixture from two contributors, a victim and an unknown culprit. There are two areas I believe will be of interest to forensic scientists, police and a Jury. These areas are identification of an individual in a DNA mixture and familial DNA database searching of a culprit through a relative. In this article, I looked at identification of individuals in a mixture using Single Nucleotide Polymorphisms (SNPs) markers. SNPs are starting to be used for forensic identification; I employed them as they produce incredible results for identification in a two-person mixture. The conservative method I employed here is the random man not excluded probability – P (RMNE) approach, an inclusion probability method generally considered as a frequentist approach. It was found that an optimum allele frequency of 0.2 is required to produce almost certain identification with much distortion in identifying an individual even when inbreeding is up to 50% in a population. Another interesting thing is that relatives of a suspect whom are actual contributors to the DNA mixture can also be identified. In a case where there are relatives in the mixture it was found that twice the number of SNP panels is required to identify an individual than in a case where no relative is involved. And lastly, typing more SNP panels helps to improve identification and therefore produce forensically useful results.

Published in International Journal of Genetics and Genomics (Volume 5, Issue 3)
DOI 10.11648/j.ijgg.20170503.11
Page(s) 27-35
Creative Commons

This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.

Copyright

Copyright © The Author(s), 2017. Published by Science Publishing Group

Keywords

SNP Markers, DNA Mixture, Allele Frequency, Likelihood Ratio, Hardy-Weinberg Equilibrium

References
[1] Butler, J. M., M. D. Coble, and P. M. Vallone, STRs vs. SNPs: thoughts on the future of forensic DNA testing. Forensic Science, Medicine, and Pathology, 2007. 3(3): p. 200-205.
[2] Budowle, B. and A. van Daal, Forensically relevant SNP classes. Biotechniques, 2008. 44(5): p. 603-8, 610.
[3] Mo, S.-K., et al., Exploring the efficacy of paternity and kinship testing based on single nucleotide polymorphisms. Forensic Science International: Genetics, 2016. 22: p. 161-168.
[4] Rapley, R. and S. Harbron, Molecular analysis and genome discovery. 2011.
[5] Kidd, K. K., et al., Developing a SNP panel for forensic identification of individuals. Forensic Sci Int, 2006. 164(1): p. 20-32.
[6] Egeland, T., I. Dalen, and P. F. Mostad, Estimating the number of contributors to a DNA profile. Int J Legal Med, 2003. 117(5): p. 271-5.
[7] Egeland, T., et al., Complex mixtures: A critical examination of a paper by Homer et al. Forensic Science International: Genetics, 2012. 6 (1): p. 64-69.
[8] Voskoboinik, L. and A. Darvasi, Forensic identification of an individual in complex DNA mixtures. Forensic Sci Int Genet, 2011. 5(5): p. 428-35.
[9] Rudin, N. and K. Inman, Likelihood Ratio and Probability of Exclusion, in An Introduction to Forensic DNA Analysis, Second Edition. 2001, CRC Press.
[10] Buckleton, J., C. M. Triggs, and S. J. Walsh, Forensic DNA Evidence Interpretation. 2004: CRC Press.
[11] Foreman, L. A. and I. W. Evett, Statistical analyses to support forensic interpretation for a new ten-locus STR profiling system. Int J Legal Med, 2001. 114 (3): p. 147-55.
[12] Saggar, A. K. and A. H. Bittles, Consanguinity and child health. Paediatrics and Child Health. 18(5): p. 244-249.
Cite This Article
  • APA Style

    Abdulwasiu Ibrahim. (2017). Identification of Individuals in a DNA Mixture Using SNP Markers. International Journal of Genetics and Genomics, 5(3), 27-35. https://doi.org/10.11648/j.ijgg.20170503.11

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    ACS Style

    Abdulwasiu Ibrahim. Identification of Individuals in a DNA Mixture Using SNP Markers. Int. J. Genet. Genomics 2017, 5(3), 27-35. doi: 10.11648/j.ijgg.20170503.11

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    AMA Style

    Abdulwasiu Ibrahim. Identification of Individuals in a DNA Mixture Using SNP Markers. Int J Genet Genomics. 2017;5(3):27-35. doi: 10.11648/j.ijgg.20170503.11

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  • @article{10.11648/j.ijgg.20170503.11,
      author = {Abdulwasiu Ibrahim},
      title = {Identification of Individuals in a DNA Mixture Using SNP Markers},
      journal = {International Journal of Genetics and Genomics},
      volume = {5},
      number = {3},
      pages = {27-35},
      doi = {10.11648/j.ijgg.20170503.11},
      url = {https://doi.org/10.11648/j.ijgg.20170503.11},
      eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijgg.20170503.11},
      abstract = {This article focuses mainly on DNA mixture from two contributors, a victim and an unknown culprit. There are two areas I believe will be of interest to forensic scientists, police and a Jury. These areas are identification of an individual in a DNA mixture and familial DNA database searching of a culprit through a relative. In this article, I looked at identification of individuals in a mixture using Single Nucleotide Polymorphisms (SNPs) markers. SNPs are starting to be used for forensic identification; I employed them as they produce incredible results for identification in a two-person mixture. The conservative method I employed here is the random man not excluded probability – P (RMNE) approach, an inclusion probability method generally considered as a frequentist approach. It was found that an optimum allele frequency of 0.2 is required to produce almost certain identification with much distortion in identifying an individual even when inbreeding is up to 50% in a population. Another interesting thing is that relatives of a suspect whom are actual contributors to the DNA mixture can also be identified. In a case where there are relatives in the mixture it was found that twice the number of SNP panels is required to identify an individual than in a case where no relative is involved. And lastly, typing more SNP panels helps to improve identification and therefore produce forensically useful results.},
     year = {2017}
    }
    

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    JO  - International Journal of Genetics and Genomics
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    AB  - This article focuses mainly on DNA mixture from two contributors, a victim and an unknown culprit. There are two areas I believe will be of interest to forensic scientists, police and a Jury. These areas are identification of an individual in a DNA mixture and familial DNA database searching of a culprit through a relative. In this article, I looked at identification of individuals in a mixture using Single Nucleotide Polymorphisms (SNPs) markers. SNPs are starting to be used for forensic identification; I employed them as they produce incredible results for identification in a two-person mixture. The conservative method I employed here is the random man not excluded probability – P (RMNE) approach, an inclusion probability method generally considered as a frequentist approach. It was found that an optimum allele frequency of 0.2 is required to produce almost certain identification with much distortion in identifying an individual even when inbreeding is up to 50% in a population. Another interesting thing is that relatives of a suspect whom are actual contributors to the DNA mixture can also be identified. In a case where there are relatives in the mixture it was found that twice the number of SNP panels is required to identify an individual than in a case where no relative is involved. And lastly, typing more SNP panels helps to improve identification and therefore produce forensically useful results.
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Author Information
  • School of Public Health, University of the Witwatersrand, Johannesburg, South Africa

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