2022年10月19日--來自佩斯大學(xué)、紐約市立約翰杰刑事司法學(xué)院和紐約市首席醫(yī)療官辦公室（OCME）的研究小組今天公布了使用forensicGEM Universal從世貿(mào)中心襲擊事件的高度降解樣本中提取DNA的發(fā)現(xiàn)。這些發(fā)現(xiàn)在法醫(yī)科學(xué)家東北部協(xié)會（NEAFS）2022年年會上的法醫(yī)生物學(xué)/DNA部分做了介紹。

自2001年9月11日的襲擊以來，OCME已經(jīng)努力確認了近20,000具遺體。而從尚待鑒定的遺體中提取核酸被公認為是最具挑戰(zhàn)性的工作，因為大部分的DNA已經(jīng)由于暴露在火、熱、飛機燃料、自然元素和老化而降解。

使用forensicGEM試劑盒，研究人員能夠從世貿(mào)中心的樣本中提取DNA，而此前使用傳統(tǒng)的提取方法是無法檢測到DNA的。

典型的法醫(yī)DNA提取行業(yè)標準使用蛋白酶K，需要多次離子清洗，孵化時間長，并且需要大量的原始樣本。ForensicGEM方法具有顯著的優(yōu)勢。使用新型的“Cocktail(雞尾酒)”嗜熱酶提取方法，提取過程中不使用洗滌劑和還原劑，forensicGEM提供的DNA提取過程不需要純化步驟，因此可以從非常少量的樣本中快速提取DNA。此外，減少的處理可以保護樣品的完整性。

研究人員首先比較了forensicGEM的孵化時間、酶量、骨骼制備方法和提取后的純化，并將其與使用非世貿(mào)中心骨骼樣本的傳統(tǒng)提取方法進行了比較。

ForensicGEM協(xié)議在80%的骨質(zhì)樣本中檢測到了DNA，而這些骨質(zhì)樣本以前沒有檢測到DNA。然后，forensicGEM被應(yīng)用于世貿(mào)中心襲擊事件的五個實際樣本，以前沒有從這些樣本中提取到可檢測的DNA，從這五個樣本中的三個提取到了DNA，并在這些高度降解的樣本中的另外兩個樣本產(chǎn)生了一個22-locus和一個15-locus的圖譜。鑒于ForensicGEM的樣品要求（10毫克）比傳統(tǒng)的提取（2克）要少得多，骨骼提取的成功是值得關(guān)注的。

研究小組表示，他們未來的研究將調(diào)查刮骨與標準的研磨方法，因為這項研究使用刮骨方法取得了更高的DNA數(shù)量和更好的輪廓。

"MicroGEM的法醫(yī)專家和應(yīng)用科學(xué)家Jillian Conte博士說："這項研究為推動圍繞骨質(zhì)樣本DNA提取的科學(xué)發(fā)展邁出了新的一步，允許進行以前不可能完成的鑒定。"我們很高興與處理這些困難樣本類型的研究小組合作，利用我們獨特的嗜熱提取能力。

MicroGEM在其最近推出的Sal6830 COVID-19診斷儀中使用了類似的核酸提取方法，這是世界上第一個在醫(yī)療點檢測SARS-CoV-2的基于唾液的PCR測試，它在30分鐘內(nèi)得到結(jié)果。

MicroGEM的法醫(yī)產(chǎn)品，包括forensicGEM Universal和forensicGEM Sperm，是從血液、組織、骨骼、唾液和精子等珍貴、有限的法醫(yī)樣本中提取DNA的理想選擇。


Extraction of Challenging Forensic Samples Using the MicroGEM DNA Extraction Kit

Lauren Chwatt, Pace University, Falyn Vega, John Jay College of Criminal Justice, James Prinston & Andrew Schweighardt, NYC Office of Chief Medical Examiner

DNA extraction is an essential but sometimes tedious process in forensic investigation that may require a significant investment of time and resources. Proteinase K has been an industry standard for DNA extraction for several decades due to its reliability of protein denaturation when performing an extraction. Some of the drawbacks of proteinase K are that its use requires multiple ionic detergents and washing steps, while only being active above 65 ̊C. Here, we analyze the potential of a new enzyme being used in DNA extraction known as forensicGEM by the manufacturer MicroGEM. This novel enzyme is temperature-dependent, which enables it to be compatible with mesophilic enzymes. The forensicGEM protocol offers complete DNA extraction in about 20 minutes in a single tube, thus limiting contamination, loss of sample, and working time -- ultimately increasing efficiency. One of the main attractions of forensicGEM is its ability to extract DNA from highly degraded samples, potentially leading to more complete STR profiles in samples where a profile may have previously been poor or unattainable by conventional extraction procedures. To assess the efficiency and potential uses of forensicGEM, we collected highly degraded tissue and bone samples and extracted DNA using the MicroGEM kit, altering different parameters such as incubation times, enzyme amount, bone preparation method, and post-extraction purification. We then compared the results of samples extracted with MicroGEM to the results of the same samples extracted with a standard organic extraction to assess whether this new technology could be utilized routinely on highly degraded samples. Half of the degraded samples extracted with MicroGEM had detectable DNA. The highest success rate was observed for bone samples. One tissue sample in particular yielded higher average peak heights when extracted with MicroGEM. No statistically significant pattern was apparent with respect to identifying superior MicroGEM optimization parameters. Success with bone profiling was notable given that there was much less sample input for MicroGEM (10 mg) compared to the organic extraction (2 g). An ancillary finding of this study is that the bone reparation method of scraping yielded higher DNA quantities and better quality profiles compared to samples treated with the standard method of milling. Since the initial results were promising, this new technology was utilized on remains from the 9/11 World Trade Center attacks from which no detectable DNA had been previously extracted. Ultimately, MicroGEM was able to yield a 22-locus and a 15-locus profile on two of these highly degraded samples. Future work will focus on further investigation of the bone scraping method for universal application, and continued optimization of experimental parameters in the MicroGEM extraction protocol.