(Roughly) Daily

Shelly Fan, with news of a new study that proports to gauge the limits of longevity…

In 1997, Jeanne Calment passed away at the age of 122 and a half. The longest living human documented to date, she pushed the boundary of what was previously considered the maximum human lifespan.

Meanwhile, in 2023, Guinness World Records recognized Pat the mouse as the oldest mouse alive at a little over nine and a half years old—just a sliver in years compared to humans.

When it comes to lifespan, we mammals have an astonishing range. The common shrew lives less than two years; bowhead whales thrive for at least 211 years. Why the discrepancy?

Part of it, according to Dr. Steve Horvath and colleagues at the University of California, Los Angeles, comes down to epigenetics: the chemical tags attached to DNA that flip genes on or off. The type and position of these tags shift through major life events—puberty, aging—and even with dietary changes.

Unlike genetics, the study of genes coded in DNA, epigenetics better captures the “here and now” of gene expression as we go through life. Previously, Horvath and others have tapped epigenetics to develop “aging clocks” that predict a person’s biological age—that is, how old your body is biologically, rather than the number of candles on your birthday cake.

In a new study in Science Advances, Horvath’s team expanded their epigenetic clocks to predict three life-changing traits: gestation time—how long the next generation fully grows in the womb—puberty, and maximal lifespan.

“Many have suggested that epigenetic mechanisms play a role in determining lifespan,” wrote the team in the paper.

Taking advantage of data from the Mammalian Methylation Consortium, they analyzed one type of epigenetic modification in over 15,000 tissue samples across 348 mammals and developed multiple epigenetic predictors for the three life-history traits across species.

The predictors were reliable. When challenged with lifestyle and demographic factors often associated with changing epigenetic markers—for example, weight, race, and biological sex—they retained their accuracy. Surprisingly, even notable methods for extending lifespan in the lab, for example, caloric restriction, had little effect on the clock’s measures.

“This [epigenetic] signature may be an intrinsic property of each species that is difficult to change,” the team wrote…

More at: “New ‘Aging Clock’ Predicts the Maximum Lifespan of 348 Mammals Including Humans,” from @ShellyFan in @singularityu.

The underlying paper, “Epigenetic predictors of species maximum life span and other life-history traits in mammals,” is here.

* Sophie Tucker

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As we age, we might send quixotic birthday greetings to Roy Walford; he was born on this date in 1924. A professor of pathology (also at UCLA), he was a pioneer in arguing for calorie restriction as a way of extending life (and a crew member of Biosphere 2.)

Walford died in 2004 at the age of 79 (though in fairness, his demise was a result of Lou Gehrig’s disease, which a could have been the result of low oxygen, high nitrous oxide levels in the Biosphere, causing the loss of brain cells).

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