Expression profile analysis and stability evaluation of 18 small RNAs in the Chinese Han population

Abstract

In recent years, differentially expressed small RNAs have been widely used to identify the compositions of forensically relevant biological samples, and a vast number of such RNA candidates have been proposed. Nevertheless, when assessing the expression levels of target small RNAs using relative quantitative analysis methods, credible internal controls are usually required for reliable data normalization. Therefore, the identification of optimal reference genes is an important task. In this study, the expression profile of 18 small RNA reference genes was characterized in the Chinese Han population using TaqMan real‐time quantitative PCR. Systematic evaluations of these candidate genes were performed based on their expression levels and stability in several common types of body fluids (i.e., venous blood, menstrual blood, saliva, semen, and vaginal secretions). Analysis results from the ΔCq method, BestKeeper, NormFinder, and geNorm were integrated by RefFinder for ranking and comparing the candidates in each type of body fluid. Among all the candidates, miR‐191 was identified as the most suitable reference gene because it had a favorable ranking value in all tested samples. In addition, miR‐423, miR‐93, miR‐484, and let‐7i were also shown to be applicable reference genes. Overall, this study provides detailed assessment results of these candidate genes in different body fluids; thus, it could be used as a guide for the selection of reference genes according to their performance in the sample of choice.

A Comprehensive Characterization of Small RNA Profiles by Massively Parallel Sequencing in Six Forensic Body Fluids/Tissue

“…However, as illustrated in Figure 7 , although there were relatively similar expression profiles between samples of the same fluid or tissue type, samples of different body fluids or tissues did not exhibit consistent expression levels. This phenomenon was also observed in another study when Wang et al evaluated the stability of 18 small RNA reference genes in five common types of body fluids (i.e., VB, MB, SA, SE, and VS) [ 69 ]. It was possible that due to the heterogeneity and complexity of small RNA expression in different body fluids or tissues, it was almost impossible to find universal small RNAs, which could be applied in all types of samples as the ideal reference gene [ 69 ].…”

“…This phenomenon was also observed in another study when Wang et al evaluated the stability of 18 small RNA reference genes in five common types of body fluids (i.e., VB, MB, SA, SE, and VS) [ 69 ]. It was possible that due to the heterogeneity and complexity of small RNA expression in different body fluids or tissues, it was almost impossible to find universal small RNAs, which could be applied in all types of samples as the ideal reference gene [ 69 ]. Hence, the optimal reference gene should be selected according to the target sample types.…”