两种DNA提取法对签字笔上脱落细胞STR分型比较

Comparison of two DNA extraction methods for STR genotyping from trace epithelial cells on fountain pen

目的 比较Chelex-100法和硅珠法两种DNA提取法,在签字笔上附着微量脱落上皮细胞分型中的应用效果.方法 17名志愿者每人使用14支签字笔,每支笔每天使用20min,为期1个月,平均分为两组,分别保存1、3、5、7、14、21和28d,同时运用Chelex-100法和硅珠法两种方法提取签字笔上遗留微量脱落细胞中的DNA,用Identifiler复合扩增系统在AB I 3100遗传分析仪上对这些DNA样品进行STR分型,同时采集上述17名志愿者口腔拭子作为对照.结果 以基因座检出个数为指标,使用后签字笔保存1、3、5、7、14、21和28d后,采用Chelex-100法和硅珠法两种方法提取DNA并进行分型检出的基因座个数相比差异均有统计学意义(P＜0.01);口腔拭子保存1、3、5、7、14、21和28d后,采用Chelex-100法和硅珠法两种方法提取DNA并进行分型检出的基因座个数相比差异均无统计学意义(P＞0.05).结论 对于微量检材,应用硅珠法提取的DNA分型效果明显优于Chelex-100法,具有较高的应用价值,而在检材量比较多时区别不明显.

Objective To compare the application effects of two DNA extraction methods for STR genotyping from trace epithelial cells on fountain pen.Methods Fourteen fountain pens were separately used by each of the 17 volunteers 20 minutes per day for a month and then were preserved on day 1,3,5,7,14,21,and 28,respectively,after the behavior.These pens were randomly divided into two groups,in which DNA was isolated from the epithelial cells on fountain pen using chelex-100 and silicon bead methods respectively.The specimens were genotyped by Identifier kit.The corresponding control samples were buccal swabs of the above volunteers.The detectable numbers of loci were counted for assessment.Results For the fountain pen which were preserved on day 1,3,5,7,14,21,28,there were statistically significant differences in the DNA genotyping by detectable numbers of gene loci between chelex-100 and silicon bead methods(P <0.01).For the corresponding oral swabs which were preserved on day 1,3,5,7,14,21,28,respectively,there were no statistically significant differences in the DNA genotyping by detectable numbers of gene loci between chelex-100 and silicon bead methods(P >0.05).Conclusion The results demonstrated that silicon bead methods was more effective than Chelex-100 methods for the trace biological samples,but when the quantity of biological samples was enough,the difference is relatively little.