Akiyama Katsunori, Yoshii Tomio, Nogami Makoto
Department of Legal Medicine, Teikyo University, School of Medicine, Kaga 2-11-1, Itabashi-ku, Tokyo 173-8605, Japan.
Leg Med (Tokyo). 2002 Sep;4(3):178-81. doi: 10.1016/s1344-6223(02)00008-1.
We analyzed the polymorphic structure of the short tandem repeat (STR) (AARG) locus D7S808 by DNA sequencing and examined the D7S808 allele distribution in a Japanese population. The sequence analysis confirmed that this locus consists of repeats of the tetranucleotides cttt and cctt, but that the number of repeats of the cctt motif does not vary with the allele, and that this STR polymorphism is due to variation in the number of cttt repeats alone. Although the results in this study suggest that the numbers of repeats range from 7 (allele 7) to 22 (allele 22), alleles 9, 10, 19, and 21 were not observed in the Japanese samples examined. Analysis of DNA samples from 355 unrelated individuals revealed the occurrence of 286 heterozygotes (observed heterozygosity 80.6%). Alleles 15, 14, 16, and 17 had high frequencies of 0.261, 0.192, 0.166, and 0.120, respectively and, together with allele 7 with a slightly high frequency of 0.059, showed a bimodal distribution. In addition, we prepared primers yielding shorter amplification products (232-292 bp) than those (435-480 bp) obtained with the originally reported primers. The newly designed primers can be used for polymerase chain reaction, making this locus extremely useful in forensic science practice.
我们通过DNA测序分析了短串联重复序列（STR）（AARG）位点D7S808的多态性结构，并检测了日本人群中D7S808等位基因的分布情况。序列分析证实，该位点由四核苷酸cttt和cctt的重复序列组成，但cctt基序的重复次数并不随等位基因而变化，并且这种STR多态性仅归因于cttt重复次数的变化。尽管本研究结果表明重复次数范围为7（等位基因7）至22（等位基因22），但在所检测的日本样本中未观察到等位基因9、10、19和21。对355名无关个体的DNA样本分析显示，有286例杂合子（观察到的杂合度为80.6%）。等位基因15、14、16和17的频率较高，分别为0.261、0.192、0.166和0.120，再加上频率略高为0.059的等位基因7，呈现双峰分布。此外，我们制备了引物，其扩增产物（232 - 292 bp）比最初报道的引物所获得的产物（435 - 480 bp）更短。新设计的引物可用于聚合酶链反应，使得该位点在法医学实践中极为有用。
