Reddy Vikram Simha A, Sriram G, Saraswathi Tr, Sivapathasundharam B
Department of Oral Pathology, G. Pullareddy Dental College, Kurnool, Andhra Pradesh, India.
J Forensic Dent Sci. 2011 Jan;3(1):27-32. doi: 10.4103/0975-1475.85293.
This study determines the importance of tooth brush from which DNA can be isolated and used for sex determination in forensic analysis.
A total of 30 samples were collected and stored at room temperature for different periods of time interval. The epithelial cells adhered to the bristles of tooth brush were collected and genomic DNA was extracted and quantified using Nanodrop 1000 spectrophotometer.
Gender identification was done by amplification of sex determining region on Y chromosome (SRY) gene using real-time polymerase chain reaction and minimal amount of DNA (in pico grams) with 100% sensitivity and 73.3% specificity, i.e., all male samples showed positive results and out of 15 female samples 4 showed false positive results, i.e wrongly identified as males.
With this study, we conclude that PCR is a valuable and sensitive procedure where minute contamination may cause alteration in the result, i.e, 4 females showed false positive result. Minute amount of DNA in picograms, which was collected at different intervals is enough for amplification of SRY gene and tooth brush can be used as one of the very valuable sources of gender identification.
本研究确定了可从中分离出DNA并用于法医分析中性别鉴定的牙刷的重要性。
共收集30个样本,并在室温下保存不同的时间间隔。收集附着在牙刷刷毛上的上皮细胞,使用Nanodrop 1000分光光度计提取并定量基因组DNA。
通过实时聚合酶链反应扩增Y染色体(SRY)基因上的性别决定区域进行性别鉴定,使用微量DNA(皮克级),灵敏度为100%,特异性为73.3%,即所有男性样本均显示阳性结果,15个女性样本中有4个显示假阳性结果,即被错误鉴定为男性。
通过本研究,我们得出结论,PCR是一种有价值且灵敏的方法,但微量污染可能会导致结果改变,即4名女性显示假阳性结果。在不同时间间隔收集到皮克级的微量DNA足以扩增SRY基因,牙刷可作为非常有价值的性别鉴定来源之一。