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Research Paper|Volume 4, Issue 7|pp 509—520

Space/Population and Time/Age in DNA methylation variability in humans: a study on IGF2/H19 locus in different Italian populations and in mono- and di-zygotic twins of different age

Chiara Pirazzini1,2, Cristina Giuliani2,3, Maria Giulia Bacalini1,2, Alessio Boattini3, Miriam Capri1,2, Elisa Fontanesi2, Elena Marasco4, Vilma Mantovani4, Michela Pierini1,2, Elisa Pini1,2, Donata Luiselli3, Claudio Franceschi1,2, Paolo Garagnani1,2
  • 1CIG - Interdipartimental Center L. Galvani, University of Bologna, Bologna, 40126, Italy
  • 2Department of Experimental Pathology, University of Bologna, Bologna, 40126, Italy
  • 3Department of Experimental Evolutionary Biology, University of Bologna, Bologna, 40126, Italy
  • 4CRBA - Applied Biomedical Research Center, S. Orsola-Malpighi Polyclinic, Bologna, 40138 Italy

* * Equal contribution

Received: June 21, 2012Accepted: July 27, 2012Published: July 31, 2012
https://doi.org/10.18632/aging.100476

Abstract

Little is known about the impact of space (geography/ancestry) and time (age of the individuals) on DNA methylation variability in humans. We investigated DNA methylation of the imprinted IGF2/H19 locus in: i) a cohort of individuals homogeneous for age and gender (males with restricted age range: 30-50 years) belonging to four Italian districts representative of the major genetic clines, informative for the geographical dimension; ii) a cohort of monozygotic (MZ) and dizygotic (DZ) twins of different ages (age-range: 22-97 years), informative for the temporal dimension. DNA methylation of the analyzed regions displayed high levels of inter-individual variability that could not be ascribed to any geographical cline. In MZ twins we identified two IGF2/H19 regions where the intra-couple variations significantly increased after the age of 60 years. The analysis of twins’ individual life histories suggests that the within twin pairs difference is likely the result of the aging process itself, as sharing a common environment for long periods had no effect on DNA methylation divergence. On the whole, the data here reported suggest that: i) aging more than population genetics is responsible for the inter-individual variability in DNA methylation patterns in humans; ii) DNA methylation variability appears to be highly region-specific.