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

在这个项目中，我们试图找到人出生后可能获得的DNA标记，并将其命名为获得性DNA标记。我们也尝试过申请他们进行个人鉴定和亲子鉴定。1993年，由于免疫球蛋白重链基因的第三互补决定区（CDR3）在b细胞分化过程中发生重排，被选择作为获得性DNA标记之一。而免疫球蛋白基因重排的成熟b细胞的寿命一般认为在2周左右。因此，我们不认为该基因是可以识别个体的获得性DNA标记。1994年，我们选择病毒基因，特别是EB病毒作为获得性DNA标记，因为这种病毒是一种人类疱疹病毒，全世界90%以上的人口携带这种病毒。利用扩增EB病毒BamW区的PCR方法，在98份外周血淋巴细胞DNA样本中检测出92%的EB病毒DNA。EB病毒DNA可能是获得性DNA标记，因为这种病毒在出生后感染人，并且很容易与宿主DNA区分。1995年，我们重点研究了EB病毒的多态性。EB病毒具有几个短串联重复序列，已知这些序列的一部分有时在无症状感染期间发生突变。因此，我们利用PCR扩增了EB病毒在外周血淋巴细胞DNA中的短串联重复序列区域，并观察了EB病毒在个体中的多态性。我们认为EB病毒可能是获得性DNA标记之一。然而，我们不知道EB病毒在人体中有多少株，也不知道EB病毒感染的时间。这些问题必须加以阐明。

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.