Yet another big hit against the genetic explanation. Not only is longevity not due to genes but it can also be largely controlled by whom you associate with.
Estimates of the Heritability of Human Longevity Are Substantially Inflated due to Assortative Mating
The Key to a Long Life Has Little to Do With ‘Good Genes’
"...“The true heritability of human longevity for that cohort is likely no more than seven percent,” says Ruby. Previous estimates for how much genes explain variations in lifespan have ranged from around 15 to 30 percent. So what did Ruby uncover that previous studies had missed? Just how often amorous humans go against the old adage that “opposites attract.” It turns out that through every generation, people are much more likely to select mates with similar lifespans than random chance would predict. The phenomenon, called “assortative mating,” could be based on genetics, or sociocultural traits, or both. For example, you might choose a partner who also has curly hair, and if the curly-haired trait winds up being somehow associated with long lifespans, this would inflate estimates of lifespan heritability passed on to your kids. Same thing for non-genetic traits like wealth, education, and access to good health care. People tend to choose partners in their same income bracket with the same terminal degree, both of which are associated with living longer, healthier lives."
"...But when Ruby looked at in-laws, things started to get weird. Logic suggests you shouldn’t share significant chunks of DNA with your siblings’ spouse—say your brother’s wife or your sister’s husband. But in Ruby’s analysis, people connected through a close relative’s marriage were almost as likely to have similar lifespans as people connected through blood. “I sort of kick myself for being surprised by this,” says Ruby. “Even though no one has shown the impact of assortative mating to such an extent before, it aligns well with how we know human societies are structured.”"
"...Maybe that’s why Ancestry’s chief scientific officer Catherine Ball says the company has no plans to offer a longevity score in any of its DNA testing products any time soon. “Right now a healthy lifespan looks to be more of a function of the choices that we make,” she says. She points to places in the data where lifespans took big hits—for males during World War I, and then in two waves in the latter half of the 20th century as men and then women took up a cigarette habit. “Don’t smoke, and don’t go to war. Those are my two pieces of advice,” she says. "
Estimates of the Heritability of Human Longevity Are Substantially Inflated due to Assortative Mating
The Key to a Long Life Has Little to Do With ‘Good Genes’
"...“The true heritability of human longevity for that cohort is likely no more than seven percent,” says Ruby. Previous estimates for how much genes explain variations in lifespan have ranged from around 15 to 30 percent. So what did Ruby uncover that previous studies had missed? Just how often amorous humans go against the old adage that “opposites attract.” It turns out that through every generation, people are much more likely to select mates with similar lifespans than random chance would predict. The phenomenon, called “assortative mating,” could be based on genetics, or sociocultural traits, or both. For example, you might choose a partner who also has curly hair, and if the curly-haired trait winds up being somehow associated with long lifespans, this would inflate estimates of lifespan heritability passed on to your kids. Same thing for non-genetic traits like wealth, education, and access to good health care. People tend to choose partners in their same income bracket with the same terminal degree, both of which are associated with living longer, healthier lives."
"...But when Ruby looked at in-laws, things started to get weird. Logic suggests you shouldn’t share significant chunks of DNA with your siblings’ spouse—say your brother’s wife or your sister’s husband. But in Ruby’s analysis, people connected through a close relative’s marriage were almost as likely to have similar lifespans as people connected through blood. “I sort of kick myself for being surprised by this,” says Ruby. “Even though no one has shown the impact of assortative mating to such an extent before, it aligns well with how we know human societies are structured.”"
"...Maybe that’s why Ancestry’s chief scientific officer Catherine Ball says the company has no plans to offer a longevity score in any of its DNA testing products any time soon. “Right now a healthy lifespan looks to be more of a function of the choices that we make,” she says. She points to places in the data where lifespans took big hits—for males during World War I, and then in two waves in the latter half of the 20th century as men and then women took up a cigarette habit. “Don’t smoke, and don’t go to war. Those are my two pieces of advice,” she says. "
given the longevity of countries around the world.
