Researchers suggest that children with older fathers and grandfathers appear to be “genetically programmed” to live longer.
The genetic make-up of sperm changes as a man gets older and develops DNA code that favors a longer life – a trait he then passes to his children, writes BBC.
The experts found the link after having analyzed the DNA of 1,779 young adults. The results of the study are to be published in Proceedings of the National Academy of Sciences.
Scientists have previously supposed that lifespan is linked to the length of structures known as telomeres that sit at the end of the chromosomes that house our genetic code, DNA. Generally, a longer telomere length means a longer life expectancy.
One function of the telomeres is to protect chromosomal ends from damage. But in most cells, they shorten with age until the cells are no longer able to replicate. However, scientists have discovered that in sperm, telomeres lengthen with age.
The telomere lengthening seen with each year that the men delayed fatherhood was equal to the yearly shortening of telomere length that occurs in middle-aged adults.
Which is more, telomere lengthening was even greater if the child’s paternal grandfather had also been older when he became a father.
“In most cells, telomeres shorten with age. But in sperm, telomeres lengthen with age,” lead researcher Dan Eisenberg, from Northwestern University’s Department of Anthropology, said.
He continued: “Men who reproduce at an older age father children with longer telomeres compared with men who reproduce at a younger age.”
Despite the fact that delaying fatherhood increases the risk of miscarriage, the researchers still believe the results of the study may be used in medicine.
“If your father and grandfather were able to live and reproduce at a later age, this might predict that you yourself live in an environment that is somewhat similar – an environment with less accidental deaths or in which men are only able to find a partner at later ages,” Eisenberg suggested.
Inheriting longer telomeres will be particularly beneficial for tissues and biological functions that involve rapid cell growth and turnover – such as the immune system, gut and skin – the scientists believe. And it could have significant implications for general population health.
“As paternal ancestors delay reproduction, longer telomere length will be passed to offspring, which could allow lifespan to be extended as populations survive to reproduce at older ages.”
Prof Thomas von Zglinicki, an expert in cellular ageing at Newcastle University, said more research was needed.
“Very few of the studies that linked telomere length to health in late life have studied the impact, if any, of paternal age. It is still completely unclear whether telomere length at conception (or birth) or rate of telomere loss with age is more important for age-related morbidity and mortality risk in humans.”
He went on: “The authors did not examine health status in the first generation offspring. It might be possible that the advantage of receiving long telomeres from an old father is more than offset by the disadvantage of higher levels of general DNA damage and mutations in sperm.”