Correction to: Is population structure in the genetic biobank era irrelevant, a challenge, or an opportunity?

Abstract

In the original article publication, there is an incorrect impression that Fig. 1 formed a formal Directed Acyclic Graph (DAG) by describing it as a causal model. However, it was not correct if interpreted in this way.

Fig. 1

Causal models including ancestry for the effect of a SNP (G) on a trait (T). The true ancestry (A) is never observed, but is measured through A₀. a Correction for stratification will be accurate when observed ancestry (A₀) is confounding T. b Correction for structure may give biased inference when observed ancestry A₀ is associated with the causal pathway by which the SNP acts, leading to a correlation in the effect of the SNP on ancestry and the trait. For example, the same SNPs are predictive of height and ancestry. Alternatively, ancestry may be associated with a trait T_A (e.g. skin tone) that causes a trait (e.g. skin cancer). c Correction for structure will be incomplete when ancestry is associated with the environment (E) due to shared history and geography (H), for example T = BMI with E = diet choice. d Correction for structure when using causal inference is robust to complexity, provided the assumptions of Mendelian randomization (see text) are met; particularly all remaining effects of ancestry go through the trait (T) so there is no direct effect of ancestry (A) on the outcome (O)