A DNA breakthrough has lead to new hopes that we might one day fully understand the ageing process - and be able to slow it down -- or halt it altogether.
Steve Horvath, professor of genetics and biostatistics at the University of California in Los Angeles, claims to have located an "internal body clock" which measures the age of our tissue.
The clock is DNA-based, and appears to regulate different types of tissue at different rates. The result is that some parts of the body appear to age faster or slower than the rest of the body.
And by learning to understand this "clock", researchers say it might be possible to develop treatments that could slow it down.
The Guardian reports that the tea behind the study looked at 8,000 samples of 51 healthy and cancerous cells, and focused on how methylation - a process that modifies DNA - changes over time.
The results showed that the methylation of 353 DNA "markers" varied in a predictable way over time, and suggested that they could be used as an objective "clock".
What isn't clear is whether the process is a cause of ageing, or a result. And without information as basic as that, it's unlikely that any kind of anti-ageing 'treatment' is going to arrive any time soon. But it's an intriguing constant to examine - giving scientists a new avenue to explore for potential treatments.
"It provides a proof of concept that one can reset the clock," said Horvath.
Other scientists reflected that scepticism, saying that an 'elixir of youth' is far from a reality.
"The general idea that you can read a genome and it reflects the ageing process is probably correct," Darryl Shibata, professor of pathology at the University of Southern California, told Forbes.
"But the weakness is that this study doesn't provide a mechanism, and without a mechanism it's just a correlation."
The study can be read in the journal Genome Biology, and more details can found over at the Guardian.