- 學位論文
台灣地區短片段重複多型性STR15型及親權指數的分析
Analysis of short tandem repeat (STR 15) polymorphisms and paternity index in Taiwan
摘要
人類基因遺傳中存在某些重複且多型性的短鏈鹼基片段，稱為短片段重複序列DNA (Short Tandem Repeat)，可做為人類多型性分析之標記。利用聚合酵素循環擴增分析法(Polymerase Chain Reaction)可大量複製特定DNA片段以產生足量之產物，再利用微細管電泳(Capillary Electrophoresis)分析法(一般經由ABI Genescan測試結果) 將人類對偶基因依其DNA片段長度之大小不同而分離，藉由DNA片段重複次數之相同或相異情形，來辨識受檢檢體之同源性或其血緣遺傳關係。刑事鑑定上常利用STR多型性當作個人身分鑑定工具。另外，在民事案件上亦可應用於血緣關係之鑑定。有關鑑定上的重要統計參數，包括鑑別率(Power of Discrimination)，同型接合性的數值 (Homozygosity Values)，異型接合性的數值(Heterozygosity Values)，吻合機率(Matching Probability)，排除率(Power of Exclusion)，以及親權指數( Paternity Index)，這些參數可以作為刑事與民事血緣鑑定之重要參考依據，其中親權指數的高低及如何定出界定值，實為認定雙方是否具親子血緣關係之重要數據。 本研究著重於交叉分析已確認親緣關係者，與無親緣關係者之親權指數(Paternity Index)之差異性，藉此探討親權指數的界定為何。吾人採集27組認為具有親子關係之家庭成員共64人，利用STR15型分析，發現STR15型可以正確鑑定此27組成員的直系血緣關係，假若將此27組家庭成員隨機配對，發現其CPI值都在1000以下，只有四組W值有達99.9%，仍不符合我國鑑定標準99.99%。研究採集之27組家庭發現有二組子女之DNA型別產生突變，依照過去計算親子指數之觀念，則可能因型別不符合而遭排除親子關係。但本研究認為親權關係排除(Paternity excluded)確定，要特別留意DNA型別突變之可能性，以免造成誤判。
並列摘要
In the human genome, there are some repetitive and polymorphic short base DNA fragments called Short Tandem Repeats (STRs), which can be used as markers for polymorphic analyses. Through Polymerase Chain Reaction, a sufficient amount of products can be generated by repeating the specific DNA fragments. Subsequently, using Capillary Electrophoresis (usually through the ABI Genescan system), the alleles are separated according to the lengths of the DNA fragments. By identifying the variations in the number of repetitive DNA fragments, the relationships between samples back-check, i.e. whether they share the same genetic source or if there is a family connection, can be determined. The versatile nature of polymorphism in the STRs has enabled it to be extensively used in both forensic identifications and parental testing. A number of statistical parameters, including Power of Discrimination, Homozygosis Values, Matching Probability, Power of Exclusion and Paternity Index, are considered as important references. The value of PI and its educated guess value are of great importance in confirming whether there is a parental relationship between the two tested parties. This study is focusing on the cross-analyses of the variations in the PI of the related confirmed by their parents, and those not. In addition, it aims to foster the discussion on how to determine the PI value. Twenty-seven groups, a total number of sixty-four people who are thought to have kinships, have taken part in this research. It is found that, by using 15 STR, the kinships among participants are correctly identified. However, when these people are randomly allocated for matching, with CPI values below 1,000, there are only four groups that have reached 99.9%, which is below the National Standard of 99.99%. On the other hand, a mutation in the DNA has been found in two children. If we were to run the test following the old method, we would most likely to reject the possibility of kinship. As a result, this research has a particular emphasis on paying attention to the possibility of DNA mutation in the Paternity Excluded Testing to avoid mistakes.