Cellular Aging Clocks Influenced by Father’s and Grandfather’s Age

The journal Proceedings of the National Academy of Sciences has a nice Fathers’ Day present for all those men who waited until they were older to finish having kids. Those molecular-scale aging clocks known as telomeres tend to be set longer for those of us with older fathers, and even more surprisingly, those of us whose fathers had older fathers. (If this is true then my cells are doubly gifted since my dad was in his late 30s when I was born and his father was about 40 when he was born). 

Telomeres are often compared to the caps on the ends of shoelaces. They protect our chromosomes and keep them from fraying. As we age, our telomeres inexorably shrink, causing the death of our cells and, eventually, us.

When we reproduce, the telomere clocks get reset in our sperm and eggs. There was some indication that Dolly the sheep and other cloned animals are born with abnormally short telomeres because they didn’t go through the normal reset process. Understanding how telomeres can be regenerated led to the 2009 Nobel Prize for a team of three researchers, including Jack Szostak, who has been featured in this blog for his work on the origin of life.

The new research on fathers' and grandfathers' age demonstrates a fascinating merger of nature and nurture, genes and environment. For years, it was verboten to consider the idea that any of us could inherit any environmentally-induced trait. That was considered wrong “Lamarckian” evolution, after the famous French evolutionist who predated Darwin but didn’t figure out natural selection.

Most of our biological inheritance is genetic and isn’t influenced by our parents’ various habits, behaviors or choices, but some so-called “epigenetic” changes do alter the chemistry surrounding the DNA. Some of those changes are lost in the production of sperm and eggs, but apparently not all of them.

Like most things, there’s an upside and a downside to having long telomeres. The downside is that long telomeres are associated with cancer cells. Building up telomeres is one of the many tricks cancer cells acquire in order to grow out of control. So it’s possible that if we ever figured out a way to keep our telomeres long, we would become more cancer-prone. It's always something.

Read the PNAS paper here:http://www.pnas.org/content/early/2012/06/05/1202092109.abstract

Read the Associated Press news report here:
 http://www.newser.com/article/d9vb42do2/tips-of-your-chromosomes-may-inherit-a-potential-health-benefit-from-your-dad-and-grandfather.html Here's an excerpt:

"One analysis of about 2,000 people confirmed the idea that the older your dad was when you were born, the longer your telomeres tend to be. That held true throughout the age range of the fathers, who were 15 to 43 at the time their sons or daughters were born.
Researchers then extended that another generation: The older your father's father was when your father was born, the longer your telomeres tend to be. That analysis included 234 grandchildren. A separate analysis found no significant effect from the mother's father.
The telomere contribution from a grandfather adds to the one from the father, researchers found.
The new work didn't look at health outcomes. That's a future step, said researcher Dan T.A. Eisenberg of Northwestern University. He presents the results with colleagues in Monday's issue of the Proceedings of the National Academy of Sciences.
Carol Greider of Johns Hopkins University, who shared a Nobel Prize in 2009 for telomere research but who didn't participate in the new study, said it's no surprise that the telomere effect would extend beyond children to grandchildren."