The Game Changer in Longevity: Unravelling the Mysteries of Epigenetics and Epigenetic Clocks
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DNA can be described as the blueprint of life that carries the instructions for building all the proteins our bodies need. However, have you ever wondered why certain genes are active in some cells but not in others, even though every cell in your body contains the exact same DNA? Have you also ever wondered why identical twins with the same DNA could end up having different health outcomes as they age? This is where the intriguing world of epigenetics comes into play.
Epigenetics can be defined as the study of changes in gene activity that do not result in any alterations to the genetic code, but still get passed on to the next generation. These changes are driven by mechanisms such as DNA methylation, histone modification, and non-coding RNAs.
DNA methylation is when a small molecule, called a methyl group attaches to a specific part of a gene, which can then change the way the gene works. In many cases, when a gene is "methylated" it is like has been switched off, and the cell machinery that would usually read that gene and follow its instructions just skips over it. Even though the gene is still there, and the underlying DNA code has not changed, the gene can't do its normal job. This process is one way that our bodies control which genes are active at which times, and in which cells.
Our cells also have a clever system to keep the DNA organised, and they wind it up around proteins called histones. This forms a structure called chromatin. The histones can be modified by adding or removing different chemical groups, such as acetyl, methyl, or phosphate groups. These modifications act like flags or signals that can change how tightly the DNA is wound around the histones.
If the DNA is wound very tightly, the genes it contains are often hidden and cannot be used by the cell. If the DNA is wound more loosely, the genes are exposed and can be used by the cell. Therefore, by modifying histones, cells can control which genes are available to be switched on and which ones are not.
DNA methylation and histone modification processes are like a set of traffic lights for genes, guiding when a gene should be turned on or off. Therefore, these “epigenetic marks” guide the cells in the body, enabling them to develop into their specific types, such as skin cells, brain cells, and muscle cells.
As mentioned above, DNA contains the instructions for making proteins and this process involves transcribing DNA into messenger RNA (mRNA), which is then used as a template to build proteins. However, not all of the RNA molecules in cells are used to make proteins. These are known as non-coding RNAs.
Certain types of non-coding RNAs can control gene activity, such as by guiding the cellular machinery to specific genes, leading to modifications of the histones around those genes, or methylation of the DNA itself. This can change how the genes are used, effectively turning them on or off without changing the underlying DNA sequence.
Other non-coding RNAs can bind to mRNA molecules and prevent them from being used to make proteins, or they can interact with proteins that control gene activity to influence their function. Even though non-coding RNAs do not make proteins themselves, it is evident that they can have a huge impact on which proteins a cell produces, and when.
Therefore, understanding epigenetics is like understanding another language that the body speaks. This gives scientists insights into how one’s behaviours, age, and environment can influence their genes and overall health.
Recent research indicates that our epigenetic marks change predictably as we age, and these changes can influence the aging process itself. This discovery led to the concept of the "epigenetic clock," which is a tool that uses the pattern of these marks to accurately measure the biological age of a person. It can be argued that this is a better indicator of health and probable lifespan than one’s chronological age (i.e. the number of years since we were born).
An epigenetic clock can also indicate how well or poorly our cells are aging. Many scientists assert that by studying and understanding the changes in our epigenetic clock, one may be able to create interventions to slow the aging process. If researchers can discover what slows down or speeds up our epigenetic clocks, this knowledge could be used to develop targeted anti-aging treatments.
An accurate measure of one’s biological age could also help predict the risk of someone developing age-related diseases, enabling earlier interventions. It could also be used to assess the effectiveness of lifestyle changes, medications, and other treatments on aging at a cellular level, which would allow one to better monitor their health.
It is clear then that one’s genetic code may be the blueprint of life, but does not tell the entire story by any means. It is the study of epigenetics and the use of epigenetic clocks (or biochemical tests used to measure one’s “real biological age”), that will guide the understanding of biology, aging, and longevity. As scientists continue to delve further into the mysteries of the epigenetic language, it can be argued the likelihood that further discoveries will be made to find keys to healthier, longer lives for each of us.
