[an error occurred while processing this directive]
法医学杂志
  首页 | 期刊介绍 | 编 委 会 | 投稿指南 | 欢迎订阅 | 广告合作 | 获奖情况 | 检索库收录情况 | 联系我们 | 友情链接 | 过期信息
法医学杂志 2018, Vol. 34 Issue (4) :370-374    DOI: 10.12116/j.issn.1004-5619.2018.04.005
论著 最新目录 | 下期目录 | 过刊浏览 | 高级检索 << | >>
推导IBS评分在无关个体对人群中概率分布的计算公式
赵焕东1,2,赵书民3,陈玉祥2,李成涛4
1. 中南大学湘雅医院 国家卫生部纳米生物技术重点实验室,湖南 长沙 410008; 2. 中南大学药学院,湖南 长沙 410013; 3. 江苏东南证据科学研究院有限公司,江苏 南京 210042; 4. 司法鉴定科学研究院 上海市法医学重点实验室 上海市司法鉴定专业技术服务平台,上海 200063
Formula Derivation for the Probability Distribution of IBS Score in Unrelated Individual Pairs
ZHAO Huan-dong1,2, ZHAO Shu-min3, CHEN Yu-xiang2, LI Cheng-tao4
1. Key Laboratory of Nanobiological Technology of Chinese Ministry of Health, Xiangya Hospital, Central South University, Changsha 410008, China; 2. School of Pharmaceutical Sciences, Central South University, Changsha 410013, China; 3. Southeast Academy of Forensic Evidence (JiangSu) Co. Ltd, Nanjing 210042, China; 4. Shanghai Key Laboratory of Forensic Medicine, Shanghai Forensic Service Platform, Academy of Forensic Science, Shanghai 200063, China

摘要
参考文献
相关文章
Download: PDF (629KB)   [ HTML ]   Export: BibTeX or EndNote (RIS)      Supporting Info
摘要 目的 推导通过STR等位基因频率计算无关个体对间状态一致性(identity by state,IBS)评分概率分布的计算公式。 方法 比较两名无关个体间某一STR基因座的基因型可以得到三种相互排斥的组合:(1)有2个相同的等位基因,此时令a2=1(否则a2=0);(2)有1个相同的等位基因,此时令a1=1(否则a1=0);(3)有0个相同的等位基因,此时令a0=1(否则a0=0);则该无关个体对在这1个STR基因座的IBS评分可采用ibs=2a2+a1计算。推导通过STR等位基因频率分别计算a2=1、a1=1和a0=1的概率(p2、p1和p0)的通用表达式,继而当该无关个体对得到n个相互独立的STR基因座分型结果时,可通过p2l和p1l计算该多重分型系统IBS评分的二项分布参数(l=1,2,…,n)。 结果 从p2、p1和p0的基本概念出发,以fi表示STR基因座第i个等位基因的频率(i=1,2,…,m),则p2的通用计算公式为p2=2(■fi2)2-■fi4;p1的通用计算公式为p1=4■fi2-4(■fi2)2-4■fi3+4■fi4,p0的通用计算公式为p0=1-4■fi2+2(■fi2)2+4■fi3-3■fi4,p2、p1、p0的和为1。IBS评分符合二项分布:IBS~B(2n,π)。其中总体率π的通用计算公式为π=■■p2l+■■p1l。 结论 生物学全同胞鉴定中的原假设为两名被鉴定人系无关个体,对任意IBS评分所对应的原假设概率均可通过本文所推导的公式进行直接计算,计算结果是进行证据解释的基础。
Service
把本文推荐给朋友
加入我的书架
加入引用管理器
Email Alert
RSS
作者相关文章
赵焕东
赵书民
陈玉祥
关键词法医遗传学   全同胞   状态一致性   二项分布   概率     
Abstract: Objective To derive the probability equation given by STR allele frequencies of identity by state (IBS) score shared by unrelated individual pairs. Methods By comparing the STR genotypes of two unrelated individuals, three mutually exclusive combinations could be obtained: (1) sharing 2 identical alleles, a2=1, otherwise a2=0; (2) sharing 1 identical allele, a1=1, otherwise a1=0; (3) sharing 0 identical allele, a0=1, otherwise a0=0. And the IBS score of the one STR locus in this unrelated individual pair could be given by the formula: ibs=2a2+a1. The probability of a2=1 (p2), a1=1 (p1) and a0=1 (p0) were derived and expressed in powers of the allele frequencies. Subsequently, for a genotyping system including n independent STR loci, the characteristics of binomial distribution of IBS score shared by a pair of unrelated individuals could be given by p2l and p1l (l=1, 2, …, n). Results All the general equations of p2, p1 and p0 were derived from the basic conceptions of a2, a1 and a0, respectively. Given fi (i=1, 2, …, m) as the ith allele frequency of a STR locus, the general equations of p2, p1 and p0 could be respectively expressed in powers of fi: p2=2(■fi2)2-■fi4, p1=4■fi2-4(■fi2)2-4■fi3+4■fi4 and p0=1-4■fi2+2(■fi2)2+4■fi3-3■fi4. The sum of p2, p1 and p0 must be equal to 1. Then, the binomial distribution of IBS score shared by unrelated individual pairs genotyped with n independently STR loci could be written by: IBS~B(2n, π), and the general probability, π, could be given by the formula: π=■■p2l+■■p1l. Conclusion In the biological full sibling identification, the probability of null hypothesis corresponding to any specific IBS score can be directly calculated by the general equations presented in this study, which is the basement of the evidence explanation.
Keywordsforensic genetics   full sibling   identity by state   binomial distribution   probability     
Fund:“十三五”国家重点研发计划资助项目(2016YFC0800703);上海市法医学重点实验室资助项目(17DZ2273200);上海市司法鉴定专业技术服务平台资助项目(16DZ2290900)
Corresponding Authors: 陈玉祥,男,研究员,博士研究生导师,主要从事药物化学研究;E-mail:yuxiangchen@csu.edu.cn 李成涛,男,研究员,博士研究生导师,主要从事法医遗传学研究;E-mail:lichengtaohla@163.com   
About author: 赵焕东(1993—),男,硕士研究生,主要从事生物医学工程研究;E-mail:zhdandy@csu.edu.cn
引用本文:   
赵焕东,赵书民,陈玉祥,等.推导IBS评分在无关个体对人群中概率分布的计算公式[J]  法医学杂志, 2018,34(4): 370-374
ZHAO Huan-dong, ZHAO Shu-min, CHEN Yu-xiang, et al..Formula Derivation for the Probability Distribution of IBS Score in Unrelated Individual Pairs[J]  法医学杂志, 2018,34(4): 370-374
Copyright 2010 by 法医学杂志