Age determination is a vital factor in biological identification in forensics. This study was carried out to determine the expression levels of three target genes (Keratin 9 (KRT9), Loricrin (LOR) and Corneodesmosin (CDSN)) in salivary epithelial cells and how they can be used in age determination using reference gene, β-actin. Thirty young adults participated in the study and were divided into three groups according to their ages (16–20, 21–25, and 26–30). Ribonucleic acid (RNA) extraction, complementary deoxyribonucleic acid (cDNA) synthesis and quantitative polymerase chain reaction (qPCR) were performed. Data analysis was done using IBM SPSS Version 26 and the comparative Ct method (2−∆∆Ct method). CDSN was detected in all the sampled age groups. Though the age group 16–20 had the highest (0.4237) expression of CDSN among the three age groups, there was no significant difference (p > 0.05) in the expression of the gene among the three age groups. The LOR gene was lowly expressed across all age groups used in the study. The expression of the gene did not significantly differ (p > 0.05) between the control and 26–30 years age group, but they were however significantly higher (F = 36.47, p ≤ 0.05) than the expression of the gene in both 16–20 and 21–25 years age groups. The KRT9 gene was expressed only in age groups 16–20 and 26–30 and the expression of the gene did not significantly (p > 0.05) differ between these age groups. Though the expression of all the target genes was low, it was observed that the LOR gene expression varied among 21–25 and 26–30 age groups; therefore, more data and further analyses are still required since this experimental approach for age determination using gene expression is still at an emerging stage. Although RNA concentration was low and the expression values of the genes were low and could not be used in comparing the expression levels among the three age groups, it can be concluded that the three messenger ribonucleic acid (mRNA) markers CDSN, LOR and KRT9, as well as the ACTB reference mRNA marker analysed via the described qPCR assays, are suitable for identifying epithelial cells in saliva.

中文翻译：

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使用唾液上皮细胞的皮肤特异性标记物进行基于信使 RNA (mRNA) 的年龄测定

年龄测定是法医生物学鉴定中的一个重要因素。本研究旨在确定唾液上皮细胞中三种靶基因（角蛋白 9 (KRT9)、Loricrin (LOR) 和 Corneodesmosin (CDSN)）的表达水平，以及如何使用参考基因​​ β- 将它们用于年龄测定。肌动蛋白。30 名年轻人参加了这项研究，并根据他们的年龄分为三组（16-20、21-25 和 26-30）。进行了核糖核酸 (RNA) 提取、互补脱氧核糖核酸 (cDNA) 合成和定量聚合酶链反应 (qPCR)。使用 IBM SPSS 26 版和比较 Ct 方法（2-ΔΔCt 方法）进行数据分析。在所有抽样年龄组中均检测到 CDSN。尽管 16-20 岁年龄组在三个年龄组中 CDSN 的表达最高（0.4237），该基因在三个年龄组之间的表达没有显着差异（p > 0.05）。LOR 基因在研究中使用的所有年龄组中均低表达。基因的表达在对照组和 26-30 岁年龄组之间没有显着差异（p > 0.05），但它们显着高于（F = 36.47，p ≤ 0.05）基因在 16-30 岁组中的表达。 20 和 21-25 岁年龄组。KRT9 基因仅在 16-20 岁和 26-30 岁的年龄组中表达，并且该基因的表达在这些年龄组之间没有显着差异（p > 0.05）。尽管所有靶基因的表达都很低，但观察到 LOR 基因表达在 21-25 和 26-30 年龄组之间存在差异；所以，由于这种使用基因表达确定年龄的实验方法仍处于新兴阶段，因此仍需要更多数据和进一步分析。尽管 RNA 浓度低，基因表达值低，无法用于比较三个年龄组的表达水平，但可以得出结论，三个信使核糖核酸 (mRNA) 标记 CDSN、LOR 和 KRT9，以及通过所述 qPCR 检测分析的 ACTB 参考 mRNA 标记物，适用于识别唾液中的上皮细胞。