Estimation of DNA degradation and STR success rate by determining the DNA degradation ratio using quantitative PCR

使用引物从基因组DNA的同一区域产生两种大小的扩增子进行定量PCR分析，以确定DNA降解的程度。在Mn^<2+>存在的情况下，DNA降解程度的分布和STR分析检测到的基因座数与DNA酶I人工降解DNA的分布具有良好的相关性。因此，DNA降解程度的测定有助于估计可检测位点的数量。使用新的DNA提取程序，我们能够从骨样本中去除与DNA共硫化的PCR抑制物质。因此，降解率对于预测案例样本中STR分析检测到的基因座数量似乎是有用的。

Quantitative PCR assays using primers that generate two sizes of amplicons from the same region of genomic DNA were used to determine the extent of DNA degradation. The distribution of the extent of DNA degradation and the number of loci detected by STR analysis in blood stains correlated well with that of DNA artificially degraded by DNase I in the presence of Mn^<2+>. Thus, determination of the extent of DNA degradation was helpful for estimating the number of detectable loci. We were able to remove the PCR inhibitory substances that were copurified with DNA from bone sample using the new DNA extraction procedure. Therefore, the degradation ratio appeared to be a useful for predicting the number of loci detected by STR analysis in casework sample.