Messenger RNA (mRNA)-based age determination using skin-specific markers of saliva epithelial cells

Abstract

BackgroundAge 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).ResultsCDSN 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.ConclusionAlthough 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.