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Published on: March 9, 2015
The effect of infertile semen on the mRNA-based body fluid identification
Huan Tian1, Sicheng Huang2, Peng Bai1
1Department of Forensic Genetics, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, Sichuan, P. R. China.
Abstract:
In the past decade, mRNA markers have been well demonstrated as promising molecular markers in forensic body fluid identification (BFI), and successfully used in wide applications. Several studies have assessed the performance of semen-specific mRNA markers in distinguishing semen from other common body fluids at the crime scene. Infertility has been reported as a global health problem that is affecting approximately 15% of couples worldwide. Therefore, it is important for forensic researchers to consider the impact of infertility on semen identification. This study aimed to explore the effect of semen from infertile men (hereinafter "infertile semen") on BFI and to identify semen-specific mRNAs that can efficiently and accurately distinguish normal and infertile semen samples from other body fluids. Results showed that the selected five mRNAs (KLK3, TGM4, SEMG1, PRM1, and PRM2) performed a significantly high semen specificity in normal semen. Moreover, KLK3 was slightly influenced by infertile semen samples with over 98% positive results in all semen samples. The accuracy to predict normal semen reached up to 96.6% using the discrimination function Y1 with KLK3 and PRM1. However, when the infertile semen samples were included in discrimination function (function Y2 with KLK3), the accuracy rate of semen identification (including the normal and infertile semen) was down to 89.5%. Besides, the sensitivity of multiplex assay could reach down to 50pg. Our results suggest that it is important to consider the presence of infertile semen when using mRNAs to identify semen samples, which would have a far-reaching impact in forensic identification.
Insights
Forensic body fluid identification using mRNA markers requires consideration of infertility. This study found that infertile semen can reduce the accuracy of semen identification, impacting forensic analysis.
Area of Science:
- Forensic Science
- Molecular Biology
- Genetics
Background:
- Messenger RNA (mRNA) markers are valuable for forensic body fluid identification (BFI).
- Previous studies focused on semen-specific mRNA markers for distinguishing semen from other fluids.
- Infertility affects a significant portion of the global population, necessitating an evaluation of its impact on forensic semen identification.
Purpose of the Study:
- To investigate the effect of infertile semen on BFI.
- To identify semen-specific mRNAs capable of differentiating normal and infertile semen from other body fluids.
- To assess the accuracy of mRNA markers in semen identification, considering infertility.
Main Methods:
- Selected five semen-specific mRNA markers (KLK3, TGM4, SEMG1, PRM1, PRM2) for analysis.
- Evaluated the specificity of these markers in normal semen samples.
- Developed discrimination functions to assess semen identification accuracy with and without infertile semen samples.
- Determined the sensitivity of a multiplex assay.
Main Results:
- The five selected mRNAs demonstrated high specificity in normal semen.
- KLK3 showed over 98% positive results across all semen samples, with slight influence from infertile samples.
- Discrimination function Y1 (KLK3, PRM1) achieved 96.6% accuracy for normal semen.
- Including infertile semen in discrimination function Y2 (KLK3) reduced accuracy to 89.5%.
- Multiplex assay sensitivity reached 50pg.
Conclusions:
- The presence of infertile semen can decrease the accuracy of mRNA-based semen identification.
- Forensic researchers must account for infertile semen in BFI protocols.
- These findings have significant implications for the reliability of forensic identification procedures.
