降解检材STR分型Ladder-Like条带形成原因的探讨

The cause of Ladder-like bands in the STR profiling of the highly degraded remains/

目的探讨降解DNA短串联重复序列PCR扩增产物在PAGE中Ladder-L ike条带的形成原因。方法用一组人工合成的不同长度的D8S1179DNA单链,模拟降解检材中的断裂DNA;利用John M设计的D8S1179引物对模拟模板的DNA单链进行PCR扩增,PAGE分离。结果不同模拟模板的DNA单链的组合可以扩增出不同的Lad-der-L ike条带。结论短串联重复序列Ladder-like条带是PCR过程中降解DNA多态区互补扩增的产物。

Objective To elucidate the mechanism of Ladder-like bands in the PCR-STR the high-degraded remains. Methods Some ssDNA of D8S1179 with one flanking sequence and profiling of several tandem repeats similar to randomly degraded DNA in decomposed remains were synthesized. The mixtures including diverse synthesized DNA possessing several repeats which can in some instances anneal complementary tandem repeat stretches are performed by PCR. Results artifact ladder is detected on PAGE. Conclusion Mimicking the components of degraded remains, in this study, we demonstrate that it is the main cause of Ladder-like artifact from decomposed remains to anneal at complementary tandem repeat in a 4bp phasing manner.