Rachel Fox reports new developments in epigenetic research
Ageing is defined biologically as the inherent and inevitable functional decline which limits lifespan. Though people swear “you’re only as old as you feel”, developments in the field of epigenetics have shown that a record of your age is written within your genes.
Discovered first in humans and characterised in mice by a group of Cambridge-based scientists (Stubbs et al 2017), there are “clock regions” in DNA: CpG islands, regions of DNA made up of alternating cytosine and guanine bases, whose methylation state correlates with age. Models generated based on these data have been able to predict age with a median error of 3.6 years in humans and 3.33 weeks in mice, whose average lifespan is 1.5-2 years. Remarkably, DNA methylation age has also been shown to be affected by smoking status, healthy eating, stress, alcohol consumption and education among other diverse lifestyle factors known to impact longevity.
The mechanism of these molecular timekeepers is unclear, and the question remains whether these marks simply correlate with or cause the progressive deterioration of ageing. Nonetheless, these results have stimulated speculation as to whether altering epigenetics could open the door to sci-fi style rejuvenation: increasing population life-span and health-span in the future. More pragmatically, since advanced age is a major risk factor for nearly all diseases, epigenetic ageing could serve as a promising biomarker for age-related diseases, or, with development, as a useful surrogate outcome measure in testing interventions to increase longevity rather than waiting decades to assess actual change in life-expectancy.