ITO法和判别函数法在同胞关系鉴定中的应用（法医学杂志2009年第25卷第4期）
(1.陆惠玲 吕德坚 章雅清 中山大学中山医学院法医物证学教研室广东广州510080；2.周科伟 佛山市安局顺德分交警队 广东 顺德528300；3.姚亚楠中山大学附属第一医院，广东广州510080)
摘 要：目的 探讨ITO法和判别函数法在全同胞、半同胞关系鉴定中的应用价值。
方法 根据500对全同胞、50对半同胞及500对无关个体的15个STR基因座(PowerPlexTM16体系)的分型结果，采用ITO法分别计算全同胞关系指数(FSI)、半同胞关系指数(HSI)及其比值(FSI:HSI)。比较三组配对个体的等位基因匹配情况，计算分型结果全不同的基因座数（xo）、半相同的基因座数（x1）和完全相同的基因座数（x2），利用 SPSS 13.0分析软件建立全同胞、半同胞和无关个体的判别函数。
结果 (1)以FSI≥19、FSI<1 作为全同胞与无关个体的判别标准，交互准确率为96.4%;以HSI≥19、HSI<1 作为半同胞与无关个体的判别标准,交互准确率为85.3%;以FSI:HSI≥1、FSI:HSI<1 作为全同胞与半同胞的判别标准，交互准确率为 87.5%。(2)分别建立了全同胞-半同胞-无关个体、全同胞-无关个体、半同胞-无关个体、全同胞-半同胞4组判别函数判别函数交互准确率为 84.4%~97.7%，其中同胞-无关个体判别准确率最高。 结论 ITO 法与判别函数法在全同胞、半同胞鉴定中均具有较高的应用价值。
关健词：法医遗传学；同胞关系；短串联重复序列；判别分析；ITO法
中国分类号：DF795.2 立献标志码：A doi：10.3969/j.issn.1004-5619.2009.02.012
文章编号：1004-5619(2009)02-0118-05
Application of ITO Method and Discriminant Functions in Full Sibling and Half Sibling Identification
LU Hui-ling1，ZHOU Ke-wei2，LU De-jian1，YAO Ya-nan3，ZHANG Ya-qing1
(1.Department of Forensic Biology，Zhonghan Medical College，Sun Yat-senUninersity，Guangzhou 510080，China；2. Traffic Police Brigade，Shunde Bramch of Foshan Public Security Bureau，Shunde 528300，China；3. The First Afiliated Hespital of Sun Yat-senUneersity，Guangzhou 510080，China)
Abstract: Objective To investigate the application of TO method and discriminant functions methed in full sibling and half sibling identification.
Methods Five hundred pairs of full siblings(FS). 50 pairs of half siblings(HS)and 500 pairs of unrelated individuals(UR) were genotyped by PowerPlex 16 system. Full sibling index(FSI). half sibling index(HSI)and the FSI:HSI ratio were calculated with ITO method Allelic matching of each pair of the three groups was compared. The locus numbers of no-allele sharing(工o)，half-allele sharing(x) and two-alleles sharing(x;) were calculated,respectively. The discriminant functions about full-siblings,half-siblings and unrelated individuals(UR) were established by SPSS 13.0 statistical software.
Results (1) Regard FSI219 or FSI<l as the standard of distinguishing full sibling from unrelated individual, the alternate correct percentage was 96.4%.Regard HSI≥19 or HSI<1 as the stan dard of distinguishing half sibling from unrelated individual, the altenate correct percentage was 85.3%. Regard FSI:HSI≥1 or FSI:HSIk1 as the standard of distinguishing full sibling from half sibling, the altenate correct percentage was 87.5%.(2)Four groups of discriminant functions were established. The alternate cor rect percentage of these discriminant functions were 84.4%-97.7%,with the highest one in full sibship- unrelated individual group. Conclusion Both ITO method and diseriminant functions method are efficient in identifieation of full sibling or half sibling.
Key words: forensic senetics; sibling relations; short tandem repeat; discriminant analysis: ITO method
