Characterising changes in expression of body fluid specific microRNA markers in vaginal material over a 31 day period

In order to maximise the effectiveness of DNA analysis, it is important to be able to identify the body fluid from which the DNA profile may have been obtained. One such technique for this is microRNA analysis. MicroRNAs are non-coding RNA’s, approximately 22 nucleotides in length, which are crucial to the regulation of genes. Their small sizemeans they are relatively stable and it has been shown thatcertainmicroRNAs are body fluid specific. A number of studies have carried out expression analysis of a large set of microRNA markers against a full body fluid panel. Once a microRNA marker has been identified as an ideal candidate, it is important that the level of expression does not significantly change over a period of time; for example, the expression of a vaginalmaterialmarker during a fullmenstrual
cycle. The changes in the cycle would suggest that the levels of expression for vaginal material and menstrual blood markers would fluctuate significantly. Here we investigate the previously identified markers for a full body fluid panel and monitor their expression levels over the full menstrual cycle in vaginalmaterial. Five volunteers provided two vaginal swabs every day for 31 days. DNA extractionwas performed on one swab and total RNA extraction on the other. All samples then underwent stem-loop reverse transcription followed by qPCR; thus indicating the relative fluctuation of body fluid specific
markers in vaginalmaterial over a fullmenstrual cycle.