The biological clock is generally considered a figure of speech, referring to a woman’s innate desire to have babies before she gets too old to carry her own child, explains MSN Healthy Living.  However, a new study published in Genome Biology indicates that the biological clock may be more than a fable.  Researchers developed a method for determining the age of a human based on DNA methylation levels.  With further investigation and refinement, this method may be able to accurately determine age using a wide variety of human cells and tissues.

Age as determined by DNA methylation holds promise as a scientifically proven biological clock.  In embryonic cells, the study found a DNA methylation “age” close to zero.  In contrast, cancer cells showed significant age acceleration in comparison to other, healthy cells.  This would be expected given the impact of cancer on morbidity and mortality.  In an analysis of the study, Forbes cautions that the research is extremely preliminary.

In a prior study, another UCLA research team that included Horvath created an age predictor that used saliva samples to determine DNA methylation levels. They then used the test to accurately predict the age of human subjects within five years, with no information other than the saliva sample. The scientists have already patented the test, which they believe could be used in forensic analysis and by doctors to predict your risk of developing age-related conditions.

The current model only shows a correlation between age and DNA methylation.  This is not to say that aging actually causes methylation, which, in turn, causes death.  If causation were found, it may be possible that, with research into slowing or reversing DNA methylation, aging could be delayed or prevented.  However, the Daily Mirror is already expressing the long-term hope of this research.  Slowing aging as a whole is a lofty goal, but targeted reduction of DNA methylation could help fight cancer.

This biological clock is known as an epigenetic clock and it works in a similar way as the circadian clock.  According to the National Institute of General Medical Sciences, the circadian clock is most well-known for regulating sleep.  However, it also regulates other physical, behavioral, and mental changes that occur over a period of 24 hours.  A number of environmental and genetic factors can influence the circadian rhythm and a disturbance of the clock can result in a variety of conditions and disorders.