Identification of complex DNA polymorphisms based on variable number of tandem repeats (VNTR) and restriction site polymorphism.

Restriction fragment length polymorphisms (RFLPs) of genomic DNA are generally attributable to base changes that create or abolish restriction endonuclease sites or to nucleotide sequence insertions or deletions that alter the distance separating two restriction sites. Minisatellite or variable number of tandem repeats (VNTR) markers are prominent examples of the latter type of polymorphism. In this report, we describe complex DNA polymorphisms that are due both to the presence of VNTRs as well as to altered restriction endonuclease sites. A strategy for identifying such polymorphisms and resolving their component allelic fragments is demonstrated.