Steve Horvath, Professor of Genetics and Biostatistics at UCLA, studied methylation, a natural process that chemically modifies DNA and how it varies with age. Horvath found that the methylation of 353 DNA markers varied consistently with age and could be used as a biological clock. Horvath showed that the biological clock was reset to zero when cells plucked from an adult were reprogrammed back to a stem-cell-like state. This may be proof of concept that the body clock can be reset.
Separately, for the first time Researchers at University of Edinburgh were able to get a working organ in a mammal to rejuvenate itself, The Economist reports. The immune-system organs called thymuses in mice were grown without any cells, relying on a chemical trigger to make the thymuses grow. It may take many more years to replicate such an organ rejuvenation in humans.
These may be future therapies to counter ageing and arrest the incurable diseases that strike in old age. Whether the DNA changes cause ageing or the changes in DNA are caused by ageing is still an unknown.
Read more at http://www.popsci.com/article/science/first-successful-regeneration-organ-mammal and http://www.theguardian.com/science/2013/oct/21/dna-body-clock-ageing