I have quite a few relatives who made it into their late eighties or even their nineties. My brother and sister and I often say we hope we have their genes.
But recent research suggests genes may not matter all that much.
Consider British zoologist and painter Desmond Morris. Having looked at the lifespan of his recent ancestors, he became convinced he’d die at the age of 60.
Reasonably enough, he decided that life was too short to waste any time, and he became a prolific author and artist. In 1967, at the age of 39, he found fame after his book The Naked Ape sold 10 million copies worldwide. It made quite a splash.
Today, Dr. Morris is still painting and writing at the age of 92. So much for genetics predicting longevity!
In fact, Dr. Morris is not unique. The latest study — and largest of its kind — shows that genes have far less influence on lifespan than many believe.
Though it’s widely believed that long life runs in families for genetic reasons, experts now believe that the contribution DNA actually makes to your longevity is roughly 15 to 30 percent. But even this may be an overestimate.
Ancestry.com Reveals New Insight into Genes and Longevity
Dr. Graham Ruby, an analyst with the Silicon Valley longevity research company Calico, felt all previous research into a person’s lifespan and genetic background was incomplete. The only way to gain a deeper insight was to analyze more data.
So, Calico teamed up with Ancestry, the parent company of Ancestry.com, which boasts the world’s largest family history database. This allowed Dr. Ruby and his research team to analyze family tree structures for almost 440 million Americans, mostly of European descent, born throughout the whole of the 19th and early 20th centuries.
Now furnished with huge amounts of data on family ties, the team examined lifespan between family members and in-laws over generations.
For siblings and first cousins of the same gender, they found genes accounted for around 20 to 30 percent of longevity, falling to 15 percent or less for relatives of different genders. This was much the same as in previous research on lifespan.
Lifestyle Link Seen in Spouses
Also, as seen in some previous research, life expectancy for a husband and wife was very similar, even more so than between a brother and sister. The researchers believe this is because spouses share the same environment and many of the same lifestyle habits.
However, something unexpected cropped up.
The lifespan among siblings-in-law and first cousins-in-law was also similar, yet they’re not blood relatives and they don’t live in the same household (at least, not usually). For example, your husband’s sister and your own sister are likely to have similar lifespans.
The same held true for even more remote relationships, such as aunts and uncles-in-law and first cousins once removed-in-law.
What factor could explain how, for instance, John’s sister’s husband’s brother could have a similar lifespan to John?
The Phenomena of “Assortative Mating”
Thanks to the massive dataset, the researchers detected a non-biological trend called assortative mating.
As explained by Dr. Ruby, “What assortative mating means here is that the factors that are important for lifespan tend to be very similar between mates. In other words, people tend to select partners with traits like their own.”
Choosing a partner is not a completely random event and usually goes against the old adage, “opposites attract.”
For instance, people with similar incomes, education and status may be more likely to marry each other. This influences lifespan and would explain similar longevity across non-family relations.
“There are a multitude of ways,” the authors wrote in the journal Genetics, “in which socioeconomic status is known to be transferred within families, and socioeconomic status is known to affect human lifespan.”
A researcher who doesn’t take assortative mating into account is likely to overestimate the impact of genetics.
When it is taken into account the impact of genetics shrinks to a mere seven percent or lower.
So, if you want to be a fit and active 92-year-old like Desmond Morris, you can largely disregard the genes you inherited. Focus instead on the choices you can control such as diet, supplements, exercise, environment and lifestyle.