From “Study: The epigenome of newborns and centenarians is different” (Medical Xpress, June 11, 2012), we learn:
the epigenome of newborns and centenarians is different.
While the genome of every cell in the human body, regardless of their appearance and function, is identical, chemical signals that regulate it, known as epigenetic marks, are specific to each human tissue and every organ. This means that all our components have the same alphabet (genome), but the spelling (epigenome) is different in every part of our anatomy. The surprising result of the work led by Dr. Esteller is that the epigenome varies depending on the age of the person, even for the same tissue or organ.
In the study published in PNAS, epigenomes from white blood cells of a newborn, a man of middle age and a person of 103 years have been fully sequenced. The results show that the centenary presents a distorted epigenome that has lost many switches (methyl chemical group), put in charge of inappropriate gene expression and, instead, turn off the switch of some protective genes.
Maybe one way of explaining it is, the epigenome is what really happens when genes apply in the real world.
See also: Centenarians’ secret is optimism?
Genetics: Can 100 100 year olds tell us how to live long?
Anyway: Too old to cut the mustard still is: