High polymorphism level of genomic sequences flanking insertion sites of human endogenous retroviral long terminal repeats.

The polymorphism at the multitude of loci adjacent to human endogenous retrovirus long terminal repeats (LTRs) was analyzed by a technique for whole genome differential display based on the PCR suppression effect that provides selective amplification and display of genomic sequences flanking interspersed repeated elements. This strategy is simple, target-specific, requires a small amount of DNA and provides reproducible and highly informative data. The average frequency of polymorphism observed in the vicinity of the LTR insertion sites was found to be about 12%. The high incidence of polymorphism within the LTR flanks together with the frequent location of LTRs near genes makes the LTR loci a useful source of polymorphic markers for gene mapping.