Estimates of the Heritability of Human Longevity Are Substantially Inflated due to Assortative Mating.
Level 3 - non-randomized controlled study
Historical pedigree cohort analysis using structural equation modeling (by design analogy)
PubMed 30401766 · doi:10.1534/genetics.118.301613
What was done
The authors analyzed large-scale genealogical pedigree data derived from Ancestry public family trees encompassing hundreds of millions of historical individuals born across the 1800s and early 1900s. They compared life span correlations between genetic relatives versus non-genetic (in-law) relatives and applied structural equation modeling to calculate life span heritability while adjusting for assortative mating.
What was found
Nominal heritability estimates from genetic relative correlations initially aligned with existing literature at approximately 15% to 30%. However, similar correlations were observed among non-genetic in-law relatives, indicating substantial assortative mating for traits influencing life span. After adjusting for assortative mating via structural equation modeling, the true heritability of human longevity across 19th- and early 20th-century birth cohorts was determined to be well below 10%.
Why it matters
This study shows that previous estimates of the genetic contribution to human life span were largely inflated by assortative mating. It indicates that genetic variation accounts for a much smaller fraction of variation in human longevity than previously assumed.
Limits
The analysis relies on crowdsourced, public family tree data, which may contain recording errors, date inaccuracies, or selection biases toward individuals whose genealogical records were preserved. Specific numerical estimates, confidence intervals, and exact sample sizes are not provided in the abstract.
Cited by
- supports Genetic inheritance accounts for no more than 10% (around 7%) of human lifespan, with about 90% driven by non-genetic factors.
- supports Studies indicate that no more than 7% to 10% of human longevity is determined by genetics.