RT Journal Article
T1 Ancestry Analysis in the 11-M Madrid Bomb Attack Investigation
A1 Phillips, Christopher Paul
A1 Prieto, Lourdes
A1 Fondevila Álvarez, Manuel
A1 Salas Ellacuriaga, Antonio
A1 Gómez Tato, Antonio
A1 Álvarez Dios, José Antonio
A1 Alonso, Antonio
A1 Blanco Verea, Alejandro José
A1 Brión Martínez, María José
A1 Montesino, Marta
A1 Carracedo Álvarez, Ángel
A1 Lareu Huidobro, María Victoria
AB The 11-M Madrid commuter train bombings of 2004 constituted the second biggest terrorist attack to occur in Europe after Lockerbie, while the subsequent investigation became the most complex and wide-ranging forensic case in Spain. Standard short tandem repeat (STR) profiling of 600 exhibits left certain key incriminatory samples unmatched to any of the apprehended suspects. A judicial order to perform analyses of unmatched samples to differentiate European and North African ancestry became a critical part of the investigation and was instigated to help refine the search for further suspects. Although mitochondrial DNA (mtDNA) and Y-chromosome markers routinely demonstrate informative geographic differentiation, the populations compared in this analysis were known to show a proportion of shared mtDNA and Y haplotypes as a result of recent gene-flow across the western Mediterranean, while any two loci can be unrepresentative of the ancestry of an individual as a whole. We based our principal analysis on a validated 34plex autosomal ancestry-informative-marker single nucleotide polymorphism (AIM-SNP) assay to make an assignment of ancestry for DNA from seven unmatched case samples including a handprint from a bag containing undetonated explosives together with personal items recovered from various locations in Madrid associated with the suspects. To assess marker informativeness before genotyping, we predicted the probable classification success for the 34plex assay with standard error estimators for a naïve Bayesian classifier using Moroccan and Spanish training sets (each n = 48). Once misclassification error was found to be sufficiently low, genotyping yielded seven near-complete profiles (33 of 34 AIM-SNPs) that in four cases gave probabilities providing a clear assignment of ancestry. One of the suspects predicted to be North African by AIM-SNP analysis of DNA from a toothbrush was identified late in the investigation as Algerian in origin. The results achieved illustrate the benefit of adding specialized marker sets to provide enhanced scope and power to an already highly effective system of DNA analysis for forensic identification.
PB PLOS
YR 2009
FD 2009
LK http://hdl.handle.net/10347/22892
UL http://hdl.handle.net/10347/22892
LA eng
NO Phillips C, Prieto L, Fondevila M, Salas A, Gómez-Tato A, Álvarez-Dios J, et al. (2009) Ancestry Analysis in the 11-M Madrid Bomb Attack Investigation. PLoS ONE 4(8): e6583. https://doi.org/10.1371/journal.pone.0006583
NO European Commission GROWTH program, SNPforID project, contract G6RD-CT-2002-00844 to CP. Xunta de Galicia, Spain: Fund PGIDTIT06PXIB228195PR and Ministerio de Educación y Ciencia, Spain: project BIO2006-06178 to MVL. Fundación de Investigación Médica Mutua Madrileña, Spain: 2006/CL370 and 2008/CL444 to AS. Continued development of the work and its application to forensic analysis is being funded by Allelyus, Santiago de Compostela, Spain
DS Minerva
RD 2 may 2026