Certain behaviors and exposure to environmental elements can have a lasting impact on gene expression by modifying chromatin at both the DNA and protein levels. These modifications comprise the field of epigenetics. Because older people have literally a lifetime of exposure to the environment, it is likely that epigenetics might play a crucial role in aging. Yet, studies of the epigenetics of aging are just in their infancy.
Researchers have found that reducing a certain epigenetic modification of proteins associated with DNA in C. elegans (a type of round worm) leads to a longer lifespan. In the November 17, 2011, issue of Nature, A. Brunet’s group at Stanford University reports that lifespan extension (resulting from the reduction of this particular epigenetic modification) is inheritable for three generations. Breeding the worms that had the extended lifespan with wild-type worms resulted in offspring that had a wild-type genome; but, surprisingly, the offspring also lived longer than normal, wild-type worms. Offspring of the second generation of worms also had a longer lifespan, as did the generation after that. The inheritance of longer life did eventually subside after four generations.
It is too early to apply this finding to human aging, but the work reveals the possibility that good (or bad) habits can have a lasting effect not only on health and lifespan, but possibly on the health and lifespan of succeeding generations. More research is needed to determine the molecular mechanisms, and to establish whether the findings can be applied to more complex organisms.
Greer EL, Maures TJ, Ucar D, Hauswirth AG, Mancini E, Lim JP, Benayoun BA, Shi Y, Brunet A. Transgenerational epigenetic inheritance of longevity in Caenorhabditis elegans. Nature. 2011 Nov 17;479(7373):302-3.