Older grandfathers pass on longer telomeres, possibly longer life

Was your grandfather already advanced in age when your father was born? If so, your DNA may help you live longer, scientists at Northwestern University reported Monday.

The reason for the seemingly counterintuitive effect? Older fathers have children with longer telomeres. Telomeres are bits of DNA at the end of chromosomes that impact aging and cell death. Generally, the longer your telomeres, the longer you live.

As we age, telomeres in our cells get shorter and shorter each time a cell divides until eventually they’re whittled away and the cell shuts down. But the opposite has been shown true in sperm cells: the older the man, the longer the telomeres in his sperm and the longer the telomeres he passes along to his offspring.

The Northwestern team’s research, which was published in the journal Proceedings of the National Academy of Sciences, added to earlier work on paternal age and telomeres by demonstrating a multi-generational influence. A paternal grandfather’s age at reproduction has as much of an effect on children’s telomere length as a father’s, they found.

The Northwestern team worked with data collected from the Phillipines’ Cebu Longitudinal Health and Nutrition Survey, which enrolled 3,327 pregnant women in 1983-1984 and followed their children. Examining telomeres in DNA collected from venous blood from the mothers and their offspring, the researchers related telomere length in mothers to their fathers’ ages when they were born. They related the younger generation’s telomere length to fathers’ ages at their birth and to grandfathers’ ages when parents were born.

The authors of the study wrote that the cumulative effect of having older fathers and grandfathers had “potentially important evolutionary implications,” suggesting a rapid adaptation to conditions promoting delayed reproduction. As men reproduce at a later age, their offspring (and grand-offspring) inherit the ability to live long enough to reproduce at later ages themselves.

“If our recent ancestors waited until later in adulthood before they reproduced, perhaps for cultural reasons, it would make sense for our bodies to prepare for something similar by investing the extra resources necessary to maintain healthy functioning at more advanced ages,” said co-author Christopher Kuzawa, an anthropologist at Northwestern, in a news release.

But that doesn’t mean men should wait around to have kids, he and his co-authors cautioned. Older fathers are still more likely to pass on harmful mutations to their children than younger fathers are.