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目的将压力循环技术(PCT)用于指甲DNA提取,并对方法学进行评价。方法收集10份人指甲样本,剪碎约为1mm×1mm大小,采用10%漂白粉水,10%SDS,10%漂白粉水,无菌水清洗样本。10份样本各分成两组,1组用压力循环技术处理,另1组不作处理,提取DNA经复合扩增并进行STR分型检测,用于评价压力循环技术的作用。取5份指甲样本用血浸泡,5份用去离子水浸泡,之后采用上述清洗方法各清洗1~3次,收集各次清洗用的无菌水提取DNA,经STR分型检测,用于评价清洗对去除外源性DNA的效果。结果 10份经压力循环技术处理的样本中有7例比相应未经处理样本DNA提取量更高,但两组进行统计学处理,差异不具有统计学意义(P>0.05);两组样本中提取DNA含量在0.026 ng以上的样本均得到完整的STR分型,与相应口腔拭子样本对照准确无误。血污染和非血污染样本清洗二次以上,均可避免外源性DNA的污染。结论使用压力循环技术并配合本文清洗方法,可有效提高人指甲DNA的提取效率,并避免外源性生物DNA的干扰,保证DNA分型结果的准确。
Objective To use pressure cycling technique (PCT) for nail DNA extraction and to evaluate methodology. Methods Ten human nail samples were collected and cut to a size of 1 mm × 1 mm. The samples were washed with 10% bleach water, 10% SDS, 10% bleach water and sterile water. Ten samples were divided into two groups. One group was treated by pressure cycling technique and the other group was untreated. The extracted DNA was amplified by multiplex amplification and subjected to STR typing to evaluate the effect of pressure cycling technology. Take 5 samples of nails soaked in blood, soaked in deionized water with 5 parts, then washed 1 to 3 times by the above cleaning method, the sterile water was collected for each cleaning DNA, detected by STR typing, for evaluation Cleaning effect on removal of exogenous DNA. Results Seven of the 10 samples treated by pressure cycling were higher than the corresponding untreated samples, but the difference was not statistically significant (P> 0.05). In both groups Complete STR typing was obtained for all samples with a DNA content of 0.026 ng or more, as compared to the corresponding buccal swab samples. Blood and non-blood contaminated samples were washed more than twice, can avoid the exogenous DNA contamination. Conclusions The use of pressure cycling technology combined with the cleaning method in this article can effectively improve the DNA extraction efficiency of human fingernails and avoid the interference of exogenous biological DNA to ensure the accuracy of DNA typing results.