Estimates predict that somewhere between 15 percent and 30 percent of the variability in human lifespan is due to genetics. But in a study published in Genetics [November 6], researchers have shown that those are likely overestimates and that assortative mating—that is, people choosing partners with traits that resemble their own—can account for most of what looks like heritability.
The Ancestry team aggregated family trees containing more than 400 million individuals, mostly American customers of European descent and their relatives. They used an algorithm to eliminate duplicates and to evaluate the accuracy of the entries—specifically, the names, dates, and locations indicated in the trees—and then de-identified the data.
The researchers used the pedigrees to calculate how similar lifespan is within families, compared to the population as a whole. Their estimates were consistent with other groups’ previous findings: somewhere between 20 percent and 30 percent of longevity appeared to be due to genetics. But the team also found correlations between lifespan in spouses that were higher than that of opposite gender siblings.
The scientists hypothesized that the similarities in length of life between spouses could be due to their shared living situation in adulthood, assortative mating, or both.
“They make a pretty convincing case that most of the previously published estimates of the heritability of longevity are probably inflated by” assortative mating, says Richard Kerber.
Read full, original post: Lifespan Less Heritable than Previously Thought