The polydeoxyadenylate tract of Alu repetitive elements is polymorphic in the human genome.

Abstract
To identify DNA polymorphisms that are abundant in the human genome and are detectable by polymerase chain reaction amplification of genomic DNA, we tested the hypothesis that the polydeoxyadenylate tract of the Alu family of repetitive elements is polymorphic among human chromosomes. We analyzed the 3' ends of three specific Alu sequences and found that two (in the adenosine deaminase gene and the beta-globin pseudogene) were polymorphic. This novel class of polymorphisms, termed AluVpA [Alu variable poly(A)] may represent one of the most useful and informative group of DNA markers in the human genome.