International Journal of Legal Medicine

, Volume 117, Issue 5, pp 302–305

Significance of micro-geographical population structure in forensic cases: a bayesian exploration

  • María T. Zarrabeitia
  • José A. Riancho
  • María V. Lareu
  • Francisco Leyva-Cobián
  • Angel Carracedo
Short Communication

Abstract

We studied the influence of population structure at the microgeographical level on the analysis of forensic cases. A total of nine autosomal STRs and seven Y-STRs were analyzed in the general mixed population and in two relatively isolated valleys of Cantabria, a region in Northern Spain. Statistically significant differences existed in the frequency distribution of four autosomal STRs, with an overall Fst value of 0.3%. A simulation of virtual trio cases revealed that it did not have a practical influence on the analysis of paternity disputes. Significant differences also existed in most Y-STRs, with an overall Fst value of 3%. Thus, using the general database instead of the specific valley database resulted in 5-fold or higher overestimation of the likelihood ratio of matching in up to 30% of cases. A bayesian analysis revealed that this had a significant impact on the estimation of the probability of identity in scenarios of low "a priori" odds of suspicion.

Keywords

Microsatellites STR Y-chromosome Evidence interpretation Population structure 

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Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  • María T. Zarrabeitia
    • 1
  • José A. Riancho
    • 2
  • María V. Lareu
    • 3
  • Francisco Leyva-Cobián
    • 2
  • Angel Carracedo
    • 3
  1. 1.Unit of Legal Medicine, Faculty of MedicineUniversity of CantabriaSantander Spain
  2. 2.Hospital Marqués de ValdecillaUniversity of CantabriaSantanderSpain
  3. 3.Institute of Legal MedicineUniversity of Santiago de CompostelaSantiago de CompostelaSpain

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