Article Summary: “Meta-analysis of … twin studies” by many


Title: Meta-analysis of the heritability of human traits based on fifty years of twin studies
Author: Tinca J C Polderman, Beben Benyamin, Christiaan A de Leeuw, Patrick F Sullivan, Arjen van Bochoven, Peter M Visscher & Danielle Posthuma
Scope: 4 stars
Readability: 1 stars
My personal rating: 4 stars
See more on my book rating system.

Topic of Book

The authors analyze virtually all twin studies published between 1958 and 2012. In total the studies involving 17,804 traits from 2,748 publications including 14,558,903 partly dependent twin pairs. The studies came from 39 different countries.

My Comments:

Until the recent advent of direct genetic text, twins studies were the gold-standard for determining the relative contributions of genes and environment. The classical twin design is based on contrasting the resemblance between identical and fraternal twins This study summarizes all their results.

Note that this article is very technical, so it is only worth reading if you are an expert in the subject. The results, however, are extremely important so it is worth reading this summary.

Key Take-aways

  • Biology wins… by a landslide!
  • Across all 17,804 traits, 49% of the variance is accounted for by heritability (i.e. biology).
  • For 69% of the traits, the variance was almost solely determined by heritability (i.e. biology)
  • There was no substantial influence from shared environment (i.e. parenting and other family factors)

Important Quotes from Book (H4)

Despite a century of research on complex traits in humans, the relative importance and specific nature of the influences of genes and environment on human traits remain controversial. We report a meta-analysis of twin correlations and reported variance components for 17,804 traits from 2,748 publications including 14,558,903 partly dependent twin pairs, virtually all published twin studies of complex traits. Estimates of heritability cluster strongly within functional domains, and across all traits the reported heritability is 49%. For a majority (69%) of traits, the observed twin correlations are consistent with a simple and parsimonious model where twin resemblance is solely due to additive genetic variation. The data are inconsistent with substantial influences from shared environment or non-additive genetic variation. This study provides the most comprehensive analysis of the causes of individual differences in human traits thus far and will guide future gene-mapping efforts.

The studies traits were grouped into the following categories:

  • Psychiatric
  • Metabolic
  • Cognitive
  • Neurological
  • Skeletal
  • Cardiovascular
  • Environment
  • Endocrine
  • Reproduction
  • Respiratory
  • Opthamological
  • Activities
  • Immunological
  • Ear, nose, throat
  • Social interactions
  • Nutritional
  • Gastrointestinal
  • Muscular
  • Hermatalogical
  • Cell
  • Neoplasms
  • Mortality
  • Aging
  • Infection
  • Development
  • Connective tissue

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