Cohort2018 · Genetics · Ruby JG et al. (Calico, Ancestry)
Ruby: lifespan heritability is only ~7% — a 400-million-person family tree
Who, how long
Family trees of 406 million people (Ancestry.com), 19th–20th century, mostly US and Europe
What they found
Spouses' lifespans correlated almost as strongly as siblings' — the earlier 20–30% heritability estimates came from assortative mating. Filtering that out, true genetic heritability is under 7%; lifespan is overwhelmingly environment and lifestyle.
⚠ Caveat
A historical cohort (infections, war, child mortality) — in today's era of chronic disease genetics may matter more; past 100 it demonstrably does.
Last reviewed: 6 September 2026
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