Length variability and interspersion patterns of the HRAS1 minisatellite: a new approach for the reconstruction of human population relationships

During recent years the HRAS1 minisatellite lias been analysed by several a uthors because of its putative association with cancer susceptibility. The aim of this report is to test the usefulness Of this minisatellite in inves tigating human population relationships. We have studied 370 chromosomes fr om two well-differentiated populations: Galicia (North-west Iberia) and Sou th-east Africa, as well as available data on allele length gene frequencies . The fragment analysis results show a strong tendency to differentiate bet ween non-African and African populations. In spite of the usefulness of fra gment analysis, the minisatellite variant repeat, (MVR) approach of the HRA S1 minisatellite appears to be a more powerful method for use in human popu lation studies, due to the high level of diversity of its interspersion pat tern structures. In addition, this approach has allowed us to define some n ew structural characteristics of this minisatellite. Four different major g roups of human HRAS1 minisatellite alleles could be distinguished following a structural criterion based on the MVR code. Furthermore, the characteris ation of the HRAS1 minisatellite in chimpanzees revealed clear differences when compared to humans, not only with respect to the allele size but also to the internal structure.