IBS法和FSI法在云南人群全同胞关系鉴定中的应用

Application of IBS and FSI Methods in the Full Sibling Testing of Yunnan Population

目的探讨IBS法和FSI法在云南人群生物学全同胞关系鉴定中的适用性。方法根据448对全同胞、1020对无关个体的19个常染色体STR分型结果,运用IBS法和FSI法计算并统计各CIBS值和CFSI值。采用SPSS 25.0软件对全同胞对和无关个体对的lgCFSI值和CIBS值分别进行描述性统计、正态检验和t检验,对计数资料采用χ^(2)检验。结果全同胞组和无关个体组的lgCFSI值和CIBS值均符合正态分布;无关个体组和全同胞组的差异在IBS法和FSI法中均具有统计学意义;统计比较旧规范和新规范中3种阈值划分方法的差异有统计学意义(P<0.001)。19个常染色体STR基因座,2种规范中3种方法的系统效能分别为0.7500,0.5565和0.6625,而研究中云南人群的系统效能分别为0.7405,0.5109和0.6621。结论新规范在云南人群全同胞关系鉴定中具有较高的法医学应用价值,基于19个常染色体STR基因座检测系统的IBS法和FSI法能有效降低全同胞关系鉴定的错判风险。

Objective To explore the applicability of IBS and FSI methods in the identification of full sibling relationship in Yunnan population.Methods A total of 448 pairs of full siblings and 1020 pairs of unrelated individuals were genotyped for 19 STR loci,and CIBS and CFSI were calculated.Descriptive statistics,normality test and t-test were performed for lgCFSI values and CIBS values of whole sibling pairs and unrelated individual pairs using SPSS 25.0 software.χ^(2)test was used for counting data.Results The lgCFSI and CIBS values of the whole sibling group and the unrelated individual group were in normal distribution.The difference between the unrelated individual group and the full sibling group was statistically significant in both the IBS and FSI methods.The statistical comparison of the difference between the three cutt-offs dividing methods in the old and new standards is statistically significant.For 19 autosomal STR loci,the system power of the three methods in the two standards were 0.7500,0.5565 and 0.6625,respectively,while the system power of the Yunnan population in this study were 0.7405,0.5109 and 0.6621,respectively.Conclusion The new standard has a high value of forensic medicine application in the identification of full sibling relationship in Yunnan.The IBS method and FSI method based on 19 autosomal STR loci detection system can effectively reduce the risk of misjudgment in the identification of full siblingrelationship.