Predicting Human Age with Bloodstains by sjTREC Quantification

Abstract

The age-related decline of signal joint T-cell receptor rearrangement excision circles (sjTRECs) in human peripheral blood has been demonstrated in our previous study and other reports. Until now, only a few studies on sjTREC detection in bloodstain samples were reported, which were based on a small sample of subjects of a limited age range, although bloodstains are much more frequently encountered in forensic practice. In this present study, we adopted the sensitive Taqman real-time quantitative polymerase chain reaction (qPCR) method to perform sjTREC quantification in bloodstains from individuals ranging from 0–86 years old (n = 264). The results revealed that sjTREC contents in human bloodstains were declined in an age-dependent manner (r = −0.8712). The formula of age estimation was Age = −7.1815Y−42.458±9.42 (Y dCtTBP-sjTREC; 9.42 standard error). Furthermore, we tested for the influence of short- or long- storage time by analyzing fresh and stored bloodstains from the same individuals. Remarkably, no statistically significant difference in sjTREC contents was found between the fresh and old DNA samples over a 4-week of storage time. However, significant loss (0.16–1.93 dCt) in sjTREC contents was detected after 1.5 years of storage in 31 samples. Moreover, preliminary sjTREC quantification from up to 20-year-old bloodstains showed that though the sjTREC contents were detectable in all samples and highly correlated with donor age, a time-dependent decrease in the correlation coefficient r was found, suggesting the predicting accuracy of this described assay would be deteriorated in aged samples. Our findings show that sjTREC quantification might be also suitable for age prediction in bloodstains, and future researches into the time-dependent or other potential impacts on sjTREC quantification might allow further improvement of the predicting accuracy.

Routes for breaching and protecting genetic privacy

“…Twin studies have estimated high heritabilities for various visible traits such as height 48 and facial morphology 49 . In addition, recent studies show that age prediction is possible from DNA specimens derived from blood samples 50,51 . But the applicability of these DNA-derived quasi-identifiers for identity tracing has yet to be demonstrated.…”

Gene analysis of signal-joint T cell receptor excision circles and their relationship to age in dogs

“…The levels of ␦Rec-J␣ sjTRECs in blood can be quantified by real-time quantitative PCR in humans (Hazenberg et al, 2001), and it is largely accepted that ␦Rec-J␣ sjTRECs are surrogate markers for thymic function (Kong et al, 1999;Wysoczanska, 2008). Previous studies have demonstrated an age-related progressive decline in blood ␦Rec-J␣ sjTREC levels (Zubakov et al, 2010;Ou et al, 2011Ou et al, , 2012Cho et al, 2014), possibly echoing age-related thymic atrophy. The measurement of blood ␦Rec-J␣ sjTREC levels and other molecular biology-based methods, including analysis of mitochondrial DNA 4977 bp-fragment deletion (Baumer et al, 1994;Hsieh et al, 1994;Lee et al, 1994;Meissner et al, 1997), telomere DNA fragment shortening (Tsuji et al, 2002;Ren et al, 2009) and methylation levels at specific genomic loci (Akira et al, 1987), have been applied to predict the age of humans for forensic purposes.…”

De-anonymizing Genomic Databases Using Phenotypic Traits

“…A thorough review of methods for predicting phenotypes from genomic data is provided in [22]. Two studies show that age prediction is feasible from DNA information derived from blood samples [30,41]. Several genome-wide studies report the influence of genomic data on height [1], body mass index (BMI) [26], eye color [38], and facial shape [8,24].…”