Longevity Briefs: New biological ageing clock shows that ageing is not a random process

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Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

Why is this research important: It was once thought by many that ageing was a completely random process, being driven by stochastic causes which triggered mutations within our DNA.

New evidence revealed by Professor Steve Horvath and his colleagues adds weight to the argument that ageing is, in fact, a process which shows consistency across species.

DNA methylation is the process in which methyl groups attach to regions of the DNA called CpG sites where they act as genetic switches, turning specific genes on or off. The increasing inaccuracy of these methyl groups to attach to the correct CpG sites as we get older is thought to be one of the root causes of ageing. By mapping which CpG sites are being unduly methylated as we age (these are called age-related CpG sites) we can build up a predictive model that can be used to assess the biological age, giving rise to biological ageing clock, otherwise known as an epigenetic clock.

What did the researchers do: Prof. Horvath et al. accumulated an unprecedentedly large collection of DNA methylation profiles of over 130 different species, from 59 different tissue types. The team located the age-related CpG sites which spanned each species and tissue type. From this, universal biological ageing clocks were generated. These can accurately predict the age of an entirely different animal, not used in the generation of the clocks.

Key takeaway(s) from this research: The data showed that the ageing of all the species shared a similar feature. Genes which are close to age-related CpG sites are intrinsically involved with the process of development. Indicating that ageing may be programmed into life through pathways linked with development and growth.

The significance of this is that it demonstrated that there may be an underlying ageing mechanism related to development which is yet to be fully explained.