T-track PCR fingerprinting for the rapid detection of genetic polymorphism.

The diversity of DNA sequences can be analyzed by comparing randomly amplified polymorphic DNA, or restriction fragment length polymorphism fragments of DNA. Such analyses are dependent on the selection of appropriate restriction enzyme(s) and/or primers. We have investigated a simpler approach to providing sensitive and specific genotyping. Cyclic extension of target sequences with dideoxythymidine generates PCR products with variable lengths. We analyzed these variable PCR products by scoring the number of variable bands and comparing the scores (numerical profiles) to establish similarities. We found that the polymorphic lengths of the PCR products were comparable among serologically defined strains. It suggests that this single PCR reaction followed by a one-step electrophoresis yields easily analyzable data that can be compared with data from other gels.