Biochemistry (Moscow)

, Volume 78, Issue 9, pp 1048–1053

How does the body know how old it is? Introducing the epigenetic clock hypothesis


DOI: 10.1134/S0006297913090113

Cite this article as:
Mitteldorf, J.J. Biochemistry Moscow (2013) 78: 1048. doi:10.1134/S0006297913090113


Animals and plants have biological clocks that help to regulate circadian cycles, seasonal rhythms, growth, development, and sexual maturity. It is reasonable to suspect that the timing of senescence is also influenced by one or more biological clocks. Evolutionary reasoning first articulated by G. Williams suggests that multiple, redundant clocks might influence organismal aging. Some aging clocks that have been proposed include the suprachiasmatic nucleus, the hypothalamus, involution of the thymus, and cellular senescence. Cellular senescence, mediated by telomere attrition, is in a class by itself, having recently been validated as a primary regulator of aging. Gene expression is known to change in characteristic ways with age, and in particular DNA methylation changes in age-related ways. Herein, I propose a new candidate for an aging clock, based on epigenetics and the state of chromosome methylation, particularly in stem cells. If validated, this mechanism would present a challenging target for medical intervention.

Key words

biological clock senescence rhythm maturation aging programmed aging adaptive aging methylation epigenetics gene expression 

Copyright information

© Pleiades Publishing, Ltd. 2013

Authors and Affiliations

  1. 1.Department of EAPSMassachusetts Institute of TechnologyCambridgeUSA

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