Does the apple fall far from the family tree?

A recent paper published in the scientific journal, Genetics, suggests that the hereditary contribution to life-span is significantly lower than previously thought. Prior studies estimated the heritability of life-span to be 15-30%, but the researchers of this current paper suggest that it is under 10%.

The study used pedigree data from hundreds of millions of people, provided by the genealogy company Ancestry. The scale of the data allowed them “to look across families over generations, analysing longevity not just in family members, but importantly among in-laws as well”, according to Cathy Ball, a co-author of the study. While the researchers initially saw heritability at similar levels to previous studies, they noted that correlation among siblings-in-law and cousins-in-law was also quite high – unusual considering that they share neither environment nor genetics. This suggested assortative mating around the genetic and environmental factors that affect life-span, that is individuals chose mating partners more genetically and/or environmentally similar to them than we would expect under random mating.

The researchers were then able to remove the statistical effects of assortative mating and improve the heritability estimate of the human life-span to around 6-7% with an uppermost estimate of 10%.  With a greater proportion of longevity the result of non-genetic influences, the development of future technologies to extend the human life-span could have an even greater effect.

The study at hand also demonstrates the kinds of large-scale patterns that only emerge when looking at data of this volume.    

 


This story is featured in the 9 November 2018 edition of The Warren Centre’s Prototype newsletter. Sign up for the Prototype here.