中文摘要：

目的验证人外周血中信号结合T细胞受体删除DNA环（signal joint T-cell receptor excision DNAcircle,sjTREC）水平与年龄的相关性公式,探讨其在鉴定实践中的应用价值。方法收集已知年龄的健康无关个体外周血痕样品30例,室温放置4周后,分别提取血痕DNA。通过实时荧光定量PCR技术,定量测定外周血痕DNA中sjTREC含量,并选择人TATA盒结合蛋白（TATA box binding protein,TBP）序列作为内参基因。采用年龄推断公式Age=-7.1815Y-42.458±9.42（Y=dCtTBP-sjTREC）推算血痕的供体年龄,并与供体实际年龄作比较,验证方法准确性。结果在收集的30例血痕样品中均能检测到目的基因sjTREC和内参基因TBP。外周血痕sjTREC含量随供体年龄的增长而降低（P〈0.01）。采用本方法推断血痕个体年龄的准确率为76.67%。结论利用sjTREC含量推断血痕个体年龄的方法简单、快速、灵敏、种属特异性好,具有重要的应用前景。

英文摘要：

Objective To determine and verify the correlation formula of age estimation using the content of signal joint T-cell receptor excision DNA circle（sjTREC） in human peripheral blood and to discuss its application value in forensic biological practice.Methods The samples of peripheral blood stains were collected from 30 healthy unrelated individuals whose ages were known.The DNAs were extracted from the samples stored at room temperature after 4 weeks.The content of sjTREC was measured by real-time fluorescent quantitative PCR technique,and the TATA box binding protein（TBP） was selected as reference genes.The age of each sample was predicted with the formula which was Age=-7.181 5 Y42.458±9.42（Y=dCtTBP-sjTREC）,and the result was compared with the real age of each individual to determine the accuracy of the formula.Results sjTREC and TBP gene were detectable in all 30 samples of peripheral blood.The contents of sjTREC in human peripheral blood showed a decreasing tendency with aging.The accuracy rate for the age estimation by this method was 76.67%.Conclusion The method for the age estimation with the content of sjTREC was simple,fast,sensitive,and good species specific with important potential application prospect.