Epigenetic age signatures in the forensically relevant body fluid of semen: a preliminary study. (November 2015)

• Record Type: Journal Article
• Authors: Lee, Hwan Young; Jung, Sang-Eun; Oh, Yu Na; Choi, Ajin; Yang, Woo Ick; Shin, Kyoung-Jin
• Is Part Of: Forensic science international. Volume 19(2015:Nov.)
• Page Start: 28
• Page End: 34
• Publication Date: 2015-11
• Subjects: Forensic science -- Age -- DNA methylation -- Semen -- TTC7B -- NOX4; Forensic genetics -- Periodicals; Génétique légale -- Périodiques; Forensic genetics; Electronic journals; Periodicals; 614.1
• DOI: 10.1016/j.fsigen.2015.05.014
• Languages: English
• ISSNs: 1872-4973

Abstract

Highlights: Previously reported age predictors were tested using 450K array data for 36 body fluid samples. Age-related CpG candidates were selected from the array results of 12 semen samples. Age-predictability of selected CpGs was tested in 68 semen samples. Age-predictive model generated with 3 CpGs showed prediction error of approximately 5 years. The CpG sites in the TTC7B gene and the NOX4 gene showed high age prediction capability. Abstract: To date, DNA methylation has been regarded as the most promising age-predictive biomarker. In support of this, several researchers have reported age predictive models based on the use of blood or even across a broad spectrum of tissues. However, there have been no publications that report epigenetic age signatures from semen, one of the most forensically relevant body fluids. In genome-wide DNA methylation profiles of 36 body fluids including blood, saliva, and semen, the previous age predictive models showed considerable prediction accuracy in blood and saliva but not in semen. Therefore, we selected CpG sites, whose methylation levels are strongly correlated with age in 12 semen profiles obtained from individuals of different ages, and investigated DNA methylation changes at these CpGs in 68 additional semen samples obtained from individuals aged 20 to 73 years using methylation SNaPshot reaction. Among the selected age-related CpG candidates, outstanding age correlation was obtained at cg06304190 in the TTC7B gene. Interestingly, the region around the TTC7B gene has been reported to show age-related DNA methylation alteration in the sperm methylome of 2 samples collected from individuals at certain time intervals. The age-predictive linear regression model trained with 3 CpGs (cg06304190 in the TTC7B gene, cg06979108 in the NOX4 gene and cg12837463) showed a high correlation between the predicted age and the chronological age, with an average absolute difference of approximately 5 years. These selected epigenetic age signatures are expected to be useful for considerably accurate age estimation in the forensically relevant body fluid of semen. However, because the findings were limited by small sample size, it will be necessary to further evaluate the age correlation of the selected CpGs and to encourage further investigation.