Genetic ancestry within Mexican families influences height and diabetes risk
A study of Mexico City families shows that Indigenous American ancestry reduces height and markedly raises type 2 diabetes risk compared with European ancestry.
Using admixed adults from the Mexico City Prospective Study, scientists estimated genome-wide ancestry proportions and examined 15 complex traits in both unrelated individuals and family members. The family-based design allowed separation of within-family ancestry effects from broader population correlations. Indigenous American ancestry showed a significant within-family reduction in height (-1.51 s.d.) and a large increase in type 2 diabetes risk (lnOR = 5.13).
By contrast, educational attainment displayed only between-family associations, suggesting environmental confounding. Analyses of trait-increasing allele counts indicated that differences in allele frequencies between ancestries contribute to the observed effects, and selection may have acted on height-related loci.
Why it matters
It reveals how genetic ancestry can directly shape health and physical traits, informing public-health strategies in diverse populations.
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