Degraded RNA transcript stable regions (StaRs) as targets for enhanced forensic RNA body fluid identification.
The detection of messenger RNA (mRNA) using reverse transcriptase PCR (RT-PCR) is becoming common practice for forensic body fluid identification. However, the degraded and scarce nature of RNA from forensic samples mean that mRNA transcripts are not consistently detected or remain undetected in practice. Conventional primer design for RT-PCR (and quantitative RT-PCR) includes targeting primers to span exon-exon boundaries or by having the primers on two separate exons, and satisfying common primer thermodynamic criteria. We have found that the conventional placement of primers is not always optimal for obtaining reproducible results from degraded samples. Using massively parallel sequencing data from degraded body fluids, we designed primers to amplify transcript regions of high read coverage, hence, higher stability, and compared these with primers designed using conventional methodology. Our findings are that primers designed for transcript regions of higher read coverage resulted in vastly improved detection of mRNA transcripts that were not previously detected or were not consistently detected in the same samples using conventional primers. We developed a new concept whereby primers targeted to transcript stable regions (StaRs) are able to consistently and specifically amplify a wide range of RNA biomarkers in various body fluids of varying degradation levels.
Forensic Research and Development, Institute of Environmental Science and Research Limited, Mount Albert, Auckland, New Zealand.
Meng-Han
MH
Lin
Forensic Research and Development, Institute of Environmental Science and Research Limited, Mount Albert, Auckland, New Zealand; School of Chemical Sciences, University of Auckland, Auckland, New Zealand.
Patricia P
PP
Albani
Forensic Research and Development, Institute of Environmental Science and Research Limited, Mount Albert, Auckland, New Zealand. Electronic address: rachel.fleming@esr.cri.nz.
Rachel
R
Fleming
D001826:Body Fluids / Q000737:chemistry*; D005260:Female; D053803:Forensic Genetics / Q000379:methods*; D006801:Humans; D008297:Male; D012313:RNA / Q000032:analysis / Q000737:chemistry* / Q000235:genetics*; D020871:RNA Stability / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis*; D012463:Saliva / Q000737:chemistry; D017423:Sequence Analysis, RNA / Q000379:methods*; D014158:Transcription, Genetic; D059467:Transcriptome
D012333:RNA, Messenger; D012313:RNA
Body fluid identification; Degraded RNA; Forensic; RNASeq; Stable transcript regions; Transcriptomics