Attaoui Asma, Foddha Hajer, Othman Houcemeddine, Ben Abdennebi Hassen, Haj Khelil Amel
Laboratory of Human Genome and Multifactorial Diseases (LR12ES07), Faculty of Pharmacy, University of Monastir, Monastir, Tunisia.
Department of Genetics, Farhat Hached University Hospital, Sousse, Tunisia.
Front Bioinform. 2025 Jun 17;5:1550730. doi: 10.3389/fbinf.2025.1550730. eCollection 2025.
This study investigates the genetic variability and forensic applicability of Short Tandem Repeat (STR) loci including autosomal, X and Y-STR markers, across distinct Tunisian regions and among sub-Saharan African populations. Our objectives were to examine the regional allelic diversity of STR markers in Tunisia, and to assess the utility of these markers for forensic differentiation between Tunisian and sub-Saharan African.
Twenty two STRs were genotyped in 500 Tunisian individuals and 501 sub-Saharan corpses by capillary electrophoresis using commercial system kits. A Chi-square test for homogeneity was applied to assess allele distribution and Principal Component Analysis to assess geographical allele variations. Bioinformatic methods in R packages were used, such as Logistic Regression Model to predict geographic group membership and Random Forest models to evaluate the discriminative power of the analyzed STRs.
Statistical analyses revealed significant allelic variability between Northern, Central, and Southern Tunisia for markers such as D1S1656, D8S1179, and CSF1PO. PCA illustrated a clear genetic distinction between Tunisian and sub-Saharan populations, largely attributable to geographical and historical gene flow barriers. LRM achieved high accuracy (95.96%) in predicting geographic affiliation. RF analysis identified DYS391 as highly discriminative in population differentiation. Our findings align with prior research on Tunisian genetic diversity and extend this knowledge by illustrating allelic frequency variations in order to establish region-specific databases.
This study contributes valuable insights into the genetic structure of Tunisian and sub-Saharan populations, emphasizing tailored approaches in forensic practices.
本研究调查了短串联重复序列（STR）位点的遗传变异性和法医学适用性，包括常染色体、X和Y染色体STR标记，涵盖不同的突尼斯地区以及撒哈拉以南非洲人群。我们的目标是研究突尼斯STR标记的区域等位基因多样性，并评估这些标记在突尼斯人和撒哈拉以南非洲人之间进行法医学区分的效用。
使用商业系统试剂盒，通过毛细管电泳对500名突尼斯个体和501具撒哈拉以南非洲尸体的22个STR进行基因分型。应用卡方同质性检验来评估等位基因分布，并使用主成分分析来评估地理等位基因变异。使用R软件包中的生物信息学方法，如逻辑回归模型来预测地理群体归属，以及随机森林模型来评估所分析STR的判别能力。
统计分析显示，在突尼斯北部、中部和南部之间，D1S1656、D8S1179和CSF1PO等标记存在显著的等位基因变异性。主成分分析表明突尼斯人群和撒哈拉以南非洲人群之间存在明显的遗传差异，这在很大程度上归因于地理和历史上的基因流动障碍。逻辑回归模型在预测地理归属方面达到了较高的准确率（95.96%）。随机森林分析确定DYS391在群体区分中具有高度判别力。我们的研究结果与之前关于突尼斯遗传多样性的研究一致，并通过阐明等位基因频率变异来扩展这一知识，以便建立特定区域的数据库。
本研究为突尼斯和撒哈拉以南非洲人群的遗传结构提供了有价值的见解，强调了法医学实践中的针对性方法。
