Micro-geographical differentiation in Northern Iberia revealed by Y-chromosomal DNA analysis

María Brion a, Bea Quintans a, Maite Zarrabeitia b, Anna Gonzalez-Neira a, Antonio Salas a, Victoria Lareu a, Chris Tyler-Smith c and Angel Carracedo a, ,

a Institute of Legal Medicine, University of Santiago de Compostela, San Francisco s/n., 15782, Santiago de Compostela, Spain
b Unit of Legal Medicine, University of Cantabria, 39011, Santander, Spain
c The Wellcome Trust Sanger Institute. Wellcome Trust Genome Campus. Hinxton, Cambs CB10 1SA, UK

Received 29 July 2003; Revised 18 November 2003; accepted 23 December 2003 Received by M. D'Urso Available online 12 February 2004.

Y-chromosome diversity has been analyzed at a micro-geographical level, examining 10 binary polymorphisms and 7 short tandem repeats (STRs) in 443 samples belonging to 11 populations from two regions of Northern Spain, Galicia and Cantabria. Both regions, as a whole, cluster with other Iberian populations. However, some individual populations, particularly that from the Pas Valley in Cantabria, depart markedly from this general pattern, with higher genetic distances and reduced diversity. This unusual population is even more distinct than the Basques from their Iberian neighbors. Genetic drift in a small isolated population could explain this special behavior, and in addition to its anthropological interest, this finding has important forensic implications.

Author Keywords: Author Keywords: Binary polymorphisms; Microsatellites; Human diversity; Population substructure; Differentiation

AMOVA, analysis of molecular variance; EDTA, Ethylenediaminetetraacetic acid; HG, haplogroup; LR, likelihood ratio; MDS, multidimensional scaling; STR, short tandem repeats