Objectives: To investigate the genetic polymorphism of InDel loci in SifalnDel 45plex system in the Han population in Jiangsu Province and the Mongolian population in Inner Mongolia, and to evaluate the effectiveness of the system in forensic medicine.
Methods: SifaInDel 45plex system was used for genotyping in blood samples of 398 unrelated individuals from the above two populations, and allele frequencies and population genetic parameters of the two populations were calculated respectively. Eight intercontinental populations in the gnomAD database were used as reference populations. The genetic distances between the two studied populations and eight reference populations were calculated based on the allele frequencies of 27 autosomal-InDels (A-InDels). The phylogenetic trees and multidimensional scaling (MDS) analysis diagrams were constructed accordingly.
Results: Among two studied populations, the 27 A-InDels and 16 X-InDels showed no linkage disequilibrium between each other and the allele frequency distributions were in Hardy-Weinberg equilibrium. The CDP of the 27 A-InDels in two studied populations were all higher than 0.999 999 999 9, and the CPEtrio were all less than 0.999 9. The CDP of the 16 X-InDels in Han in Jiangsu and Mongolian in Inner Mongolia female and male samples were 0.999 997 962, 0.999 998 389, and 0.999 818 940, 0.999 856 063, respectively. The CMECtrio were all less than 0.999 9. The results of population genetics showed that the Jiangsu Han nationality, Inner Mongolia Mongolian nationality and East Asian population clustered into one branch, showing closer genetic relationship. The other 7 intercontinental populations clustered into another group. And the above 3 populations displayed distant genetic relationships with the other 7 intercontinental populations.
Conclusions: The InDels in the SifaInDel 45plex system have good genetic polymorphism in the two studied populations, which can be used for forensic individual identification or as an effective complement for paternity identification, and to distinguish different intercontinental populations.
目的: 调查SifaInDel 45plex体系所含InDel位点在我国江苏汉族和内蒙古蒙古族人群中的遗传多态性，并评估该体系的法医学应用效能。方法: 应用SifaInDel 45plex体系对上述2个民族共398名无关个体血样进行等位基因分型检测，分别计算2个研究人群的等位基因频率和群体遗传学参数；以gnomAD数据库中8个不同洲际人群为参考群体，基于27个常染色体InDel位点的等位基因频率，计算2个研究人群与8个参考人群间的遗传距离，并构建系统发育树和多维尺度分析图。结果: 2个研究人群中，27个常染色体InDel、16个X染色体InDel位点间均不存在连锁不平衡，等位基因频率分布均符合Hardy-Weinberg平衡。27个常染色体InDel位点在2个研究人群中的CDP均高于0.999 999 999 9，CPEtrio均小于0.999 9。16个X染色体InDel位点在江苏汉族和内蒙古蒙古族女性群体和男性群体中的CDP分别为0.999 997 962、0.999 998 389和0.999 818 940、0.999 856 063，CMECtrio均小于0.999 9。群体遗传学研究结果表明，江苏汉族、内蒙古蒙古族与东亚人群间遗传关系较近，聚为一支；其他7个洲际人群聚为另一支；上述3个人群与其他7个洲际人群间遗传关系较远。结论: SifaInDel 45plex体系中的遗传标记在本研究2个民族人群中具有良好的遗传多态性，可用于法医学个体识别或作为亲权鉴定的有效补充，并可用于区分不同洲际人群。.
Keywords: forensic genetics; genetic distance; genetic polymorphism; insertion/deletion (InDel); multidimensional scaling analysis; phylogenetic tree.