A male and female RNA marker to infer sex in forensic analysis. (January 2017)

• Record Type: Journal Article
• Authors: van den Berge, M.; Sijen, T.
• Is Part Of: Forensic science international. Volume 26(2017:Jan.)
• Page Start: 70
• Page End: 76
• Publication Date: 2017-01
• Subjects: Forensic science -- mRNA profiling -- Body fluid identification -- Organ tissue identification -- Sex-specific RNA marker -- Sex-biased genes; Forensic genetics -- Periodicals; Génétique légale -- Périodiques; Forensic genetics; Electronic journals; Periodicals; 614.1
• DOI: 10.1016/j.fsigen.2016.10.018
• Languages: English
• ISSNs: 1872-4973

Abstract

Highlights: Two sex-biased genes are found suitable to infer sex in RNA assays. XIST is female-expressed from its function in X-chromosome inactivation. RPS4Y1 is Y-chromosome-specific and therefore male-expressed. Both markers are incorporated in two multiplexes targeting body fluids or organs. These assays were validated for casework. Abstract: In forensics, DNA profiling is used for the identification of the donor of a trace, while messenger RNA (mRNA) profiling can be applied to identify the cellular origin such as body fluids or organ tissues. The presence of male cell material can be readily assessed by the incorporation of Y-chromosomal markers in quantitation or STR profiling systems. However, no forensic marker exists to positively identify female cell material; merely the presence of female DNA is deduced from the absence of a Y peak, or unbalanced X-Y signals at the Amelogenin locus or unbalanced response of the total and Y-specific quantifier. The presence of two X-chromosomes in female cells invokes dosage compensation, which is achieved through inactivation of one of the X-chromosomes in females. Since this process involves specific RNA molecules, identification of female cellular material may be possible through RNA profiling. Additionally, male material may be identified through RNAs expressed from the Y-chromosome. RNAs preferentially expressed in either sex were assessed for their potential to act as sex markers in forensic RNA assays. To confirm sex-specificity, body fluids and organ tissues of multiple donors of either sex were tested. Additionally, sensitivity of the markers and the suitability of positively identifying male-female mixtures were assessed and degraded samples were used to assess performance of the markers in forensic settings. The addition of sex-specific markers is of added informative value in any RNA profiling system and both markers were incorporated into existing RNA assays that either target body fluids or organs. These are the first forensic assays that enable positive identification of female cellular material.