The study of virus DNA polymorphisms and its application to paternity testing

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In this project, we have tried to find the DNA markers that might be acquired in persons after their birth and be named acquired DNA markers. We have also tried to apply them for personal identification and paternity testing. In 1993, the third complementarity-determining region (CDR3) of immunoglobulin heavy chain gene was selected as one of acquired DNA markers, because this gene was rearranged during B-cell differentiation. However, the life span of the mature B-cells whose immunoglobulin gene was rearranged is generally considered to be about 2 weeks. Therefore, we did not think that this gene was the acquired DNA marker that could identify individuals. In 1994, we selected virus genes, especially Epstein-Barr (EB) virus as the acquired DNA marker, because this virus is a human herpesvirus that is carried by more than 90% of human population worldwide. We could detect the EB virus DNA in 92% of 98 DNA samples from peripheral blood lymphocytes using PCR that amplified BamW region of EB virus. EB virus DNA might be the acquired DNA marker, because this virus infects persons after their birth, and could be easily differentiable from the host DNA.In 1995, we focused the polymorphism of EB virus. EB virus has several short tandem repeat sequences and it is known that part of these sequences sometimes mutate during asymptomatic infection. So, we amplified the region of short tandem repeats of EB virus in the DNA isolated from peripheral blood lymphocytes using PCR and could observe the polymorphisms of EB virus in individuals. We concluded that EB virus might be considered as one of acquired DNA markers. However, we don't know how many strains of EB virus there are in persons, or how long EB virus is infected. These subjects will be had to elucidated.