Molecular Investigation and Estimation of Time

Molecular Investigation and Estimation of Time

Department Genetic Identification

When time passes by, molecular changes in the human body or body parts occur. We are interested in molecular footprints of time in different aspects. On one side, we consider time as the 24 hours of a day/night cycle, and establish rhythmic molecular biomarkers. Besides achieving a better understanding in human chronobiology and its molecular basis, which is of health relevance, we envision the use of such biomarkers for estimating day/night time from human biological samples. One area of application is in forensics, where estimating the time when a sample was placed at the crime scene would provide direct means for alibi testing. For instance, we showed that obtaining rhythmic profiles of hormones and mRNAs from small amounts of blood not only is feasible but moreover allows the establishment of statistical models for estimating time intervals within a day/night cycle. On the other side, we consider time as age in two aspects i) age of a human biological sample, and ii) age of a person. To search for possibilities of molecular estimation of sample age, we study in-vitro differences in the degradation patterns of various biomarkers. For molecular estimation of a person’s age, we investigate the relationship of DNA and RNA variation with age, and develop biomarkers of age. For instance, we demonstrated that a particular DNA re-arrangement, existing in certain blood cells only, allows estimating accurately a person’s age on the age group level. We also study the genetic basis of various age-related appearance phenotypes (see appearance genetics). 

Selected relevant publications:

• Lech K et al. Evaluation of mRNA markers for estimating blood deposition time: Towards alibi testing from human forensic stains with rhythmic biomarkers. Forensic Sci Int Genet. 2016 21: 119–125 [PubMed: 26765251]
• Lech et al. Dissecting Daily and Circadian Expression Rhythms of Clock-Controlled Genes in Human Blood. J Biol Rhythms. 2016 31: 68-81. [PubMed: 26527095]
• Russcher et al. An observational study on disturbed peripheral circadian rhythms in hemodialysis patients. Chronobiol Int. 2015 32: 848-57. [PubMed: 26101944]
• Davies et al. Effect of sleep deprivation on the human metabolome. Proc Natl Acad Sci U S A. 2014 111: 10761-6. [PubMed: 25002497]
• Lech et al. Assessing the suitability of miRNA-142-5p and miRNA-541 for bloodstain deposition timing. Forensic Sci Int Genet. 2014 12: 181-4. [PubMed: 24999280]
• Ackermann et al. Effect of sleep deprivation on rhythms of clock gene expression and melatonin in humans. Chronobiology International. 2013 30: 901-9. [PubMed: 23738906]
• Ackermann et al. Diurnal rhythms in blood cell populations and the effect of acute sleep deprivation in healthy young men. Sleep. 2012 35: 933-40. [PubMed: 22754039]
• Kayser, M., de Knijff, P. Improving human forensics through advances in genetics, genomics and molecular biology. Nat Rev Genet. 2011 12: 179-92. [PubMed: 21331090]
• Ackermann et al. Estimating trace deposition time with circadian biomarkers: a prospective and versatile tool for crime scene reconstruction. Int J Legal Med. 2010 124: 387-95. [PubMed: 20419380]
• Zubakov et al. Estimating human age from T-cell DNA rearrangements. Curr Biol. 2010 20: R970-1. [PubMed: 21093786]