Diversity of a Superimposed Alu Dimorphic Variant in Human Populations. Nageswara R. Alla and David H. Kass, Eastern Michigan University, Department of Biology, Ypsilanti, MI 48197 Alu represents the predominant family of short interspersed DNA dements SINEs) within primate genomes. These are considered retrotransposons as they accumulate within the genome via an RNA intermediate. This process referred to as retrotranspositioncontinues within the human genome, with estimates of about one new integration event in one hundred births. Recent integrations may not he fixed within human populations and therefore provide useful presence/absence DNA markers. These dimorphic Alu elements have been utilized in a variety of regional and global human population studies. In this study, we have identified an Alu presence allele that demonstrates three different small-length variants. Therefore, this superimposed variant can potentially enhance the usefulness of this marker, and add to a small but growing number of these types of markers. We are investigating the nature of the variation and analyzing DNA samples from a variety of ethnic groups to assess its potential as a population marker. Superimposed Alu markers may provide a unique tool in the study of human populations.
