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Title: | 提昇法醫檢體精斑檢測技術之研究 The research in improving the forensic identification of semen stain form sexual assault evidences |
Authors: | Yu-En Chen 陳羽恩 |
Advisor: | 曾麗慧(Li-Hui Teng) |
Keyword: | 精斑鑑定,差異萃取法,核酸?,個化, sperm identification,differential extraction,nuclease,individualization, |
Publication Year : | 2016 |
Degree: | 碩士 |
Abstract: | 法醫工作中常遇到需檢測精斑之檢體,然而在實務上以差異萃取法(differential extraction)進行精蟲細胞DNA萃取,卻常面臨到檢體嚴重腐敗、精蟲裂解、大量女性上皮細胞DNA競爭PCR等問題,而導致男性STR DNA 型別鑑驗不佳,精子細胞層呈現混合型別,難以個化嫌犯,故本研究引進核酸酶改良式差異萃取法(Erase sperm isolation kit),收集3組男女標準檢體先進行方法確校,確立方法之重複性、靈敏度、檢測時效,並同時與傳統差異萃取法比較優劣,其結果顯示傳統差異萃取法在精蟲細胞層均呈現混合型別,而核酸酶改良式差異萃取法可精準分離出男性單一型別,模擬48小時後腐敗之檢體,其精蟲細胞層仍可完整分析出男性STR DNA型別,當確認核酸酶改良式差異萃取法之有效性後,本研究收集4組法醫實務案件檢體進行傳統差異萃取法及核酸酶改良式差異萃取法之比較,結果顯示以傳統差異萃取法其精蟲細胞層有3案為男女混合型別、1案仍維持女性單一型別,而以核酸酶改良式差異萃取法4案均可分析出男性單一型別,此外本研究亦同時收集18案實務精斑檢體,其中14案精蟲細胞層同樣可分析出男性單一型別,另外2案則為多人(2名以上男性精蟲細胞)男性混合型別,2案檢體因腐敗等因素仍呈現混合型別,綜上所述,核酸酶改良式差異萃取法相較於傳統差異萃取法,實驗的過程減少細胞洗滌的耗損、避免精蟲細胞提前消化,大幅提高男性精蟲細胞的檢出,並且明確分離出精蟲細胞層男性STR DNA單一型別,以利個化嫌犯,期望將此方法引進國內供法醫及鑑識單位參考,未來面對性侵害、姦殺等案件能夠迅速分型出男性型別,彰顯司法正義,維護社會秩序安寧。 It is customary in forensics work to analyze sperm samples. In reality, differential extraction, the extraction of sperm DNA, professionals are often faced with many difficulties. These problems include corrupted samples, sperm autolysis, large amounts of female epithelial DNA competing with that of male sperm DNA in PCR, etc, which produces poor male STR DNA test results wherein the sperm cell layer is mixed, making it hard to narrow down to a more specific suspect.This study collected 3 sets of standard male/female samples to use in the modified-nuclease differential extraction (Erase sperm isolation kit), where they are validated, checked for repeatability and sensitivity, and detected for effectiveness. The results are then compared with that of traditional differential extraction to investigate the advantages and limitations.Results from differential extraction showed mixed sperm cell layer presentation, while Erase sperm isolation kit can accurately extract cell materials of the male gender. In a simulated post 48-hr corrupted sample scenario, the sperm cell layer could still be successfully extracted and completely analyze its male STR DNA type. Once the Erase sperm isolation kit is confirmed for its effectiveness, four sets of forensics case samples were tested using this method as well as the differential extraction method for comparison. Results revealed that with the extraction method, 3 cases were of mixture type and 1 remained female type, while with the erase sperm isolation kit yielded all four cases with male type. This study also collected 18 sperm samples from real-life, forensics cases, 14 of which were of single male type, 2 were of multi-person mixture type, and 2 were corrupted and presented as mixture type. In conclusion, the Erase sperm isolation kit, compared to the traditional differential extraction, eliminated the material loss from cell wash and prevented premature sperm cell lysis, this dramatically increased the likelihood of extracting the male sperm cell material and accurately extracting STR DNA single male type, thus facilitating individualization of the suspect in an ongoing investigation. We hope that this method be utilized in respective domestic forensic units for reference in future cases of sexual assault, rape-kill to rapidly extract the male cell type, bring crimes to justice, and maintain social order and peace in Taiwan. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/19105 |
DOI: | 10.6342/NTU201602313 |
Fulltext Rights: | 未授權 |
Appears in Collections: | 分子醫學研究所 |
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ntu-105-1.pdf Restricted Access | 1.51 MB | Adobe PDF |
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