未消化蕃茄種子DNA分析在刑事鑑識之應用

DNA Analysis of Ingested Tomato Seeds in Forensic Applications

李承龍(Cheng-Long Li)

指導教授 ： 許志楧 博士 ； 李昌鈺 博士 ； Dr. Heather Miller Coyle

國立清華大學/原子科學院/生醫工程與環境科學系/博士(2007年)

https://doi.org/10.6843/NTHU.2007.00055

摘要

中文摘要
未消化的食物是法醫解剖的重要證物之一，因為它們可能在犯罪偵查上扮演重要的角色，除了研判死亡時間外，亦可確認最後一餐的飲食情況，進而追溯出餐飲處所或食用的蔬果種類。未消化的食物，例如種子，有時可能成為關鍵的重要線索，協助外勤人員偵查犯罪、預測死亡時間及確認證詞的可靠性等。
目前，有關辨識種子的方法仍借重於顯微鏡的外觀比對，但我們發現，未消化之蕃茄與青椒種子間或變種蕃茄的種子間，皆不易以其外表特徵來區分。而蕃茄及青椒又經常在各種菜餚中出現，因此在本論文中，我們挑選它們的種子，當作種屬及變種分析的模型樣品，藉以評估利用DNA分析來區分未消化種子的可行性。本論文的研究成果包含下列四部分：一、僅用蕃茄的半顆種子，即可萃取到高品質的新鮮及未消化蕃茄種子DNA；二、在六十四組引子對商品中，找到一組最佳的引子對，所分析得到的DNA-AFLP特徵圖譜，即可研判蕃茄及青椒的種子異同；三、利用一組引子對所得DNA-AFLP特徵圖譜的分析方式，即可區分五種不同變種蕃茄間種子的異同；四、在十二種常見蕃茄產品及烹煮、烘烤過的種子中，無法萃取到可偵測的DNA。
本論文建立利用兩類（蕃茄、青椒）不同種的植物和五種不同變種蕃茄間的DNA-AFLP特徵圖譜分析種子異同的方法，可用來辨識排泄物或胃內容物的種子種類，藉以追溯食物的來源，此一技術將為鑑識科學增添另一利器，彌補以往對於非人類證物鑑定能力之不足，以提供警方偵辦相關刑案之需求。

關鍵字

鑑識科學 ； 刑事植物學 ； 胃內容物 ； 蕃茄種子 ； 青椒種子 ； 種子鑑定 ； 擴增區段長度多型性

並列摘要

ABSTRACT
Indigestible material is one of the important evidences in autopsy. Stomach content analysis will also provide qualitative information concerning the decedent’s last meal and to link the suspect or a location through the identification of source of the food. Ingested items such as seeds could become key evidence for providing leads in criminal investigations, estimate the time of death or verify an alibi.
Currently, the identification of seeds still relies on microscopical examination. We found that it is hard to distinguish between the seeds of ingested cultivars of tomato and between tomato and pepper. In this dissertation, tomato and pepper seeds were selected as a model system for the species identification and cultivars identification since they are commonly found in a variety of cuisines. Our results revealed that (i) high quality DNA from a half ingested tomato seed could be isolated; (ii) Find one optimal primers from 64 primers kits and using the primer’s DNA-AFLP pattern could be used to discriminate between tomato and pepper species; (iii) Only one primer’s DNA-AFLP pattern could be used to discriminate between different tomato cultivars; (iv) DNA could not be isolated from tomato seeds of 12 commercial products, home cooked and baked seeds
My dissertation established a new method to distinguish two species and five cultivars. These results indicate that AFLP is a viable procedure for the identification of seed varieties from feces or stomach contents, thus adding an additional tool to identify nonhuman evidence for criminal investigations.

並列關鍵字

forensic science ； forensic botany ； stomach content ； tomato seed ； pepper seed ； seed identification ； amplified fragment length polymorphism

參考文獻

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