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Fig. 1 | Genome Biology

Fig. 1

From: Impact of admixture and ancestry on eQTL analysis and GWAS colocalization in GTEx

Fig. 1

Population admixture in the GTEx v8 cohort. a Genotype principal components (gPCs) reflect global ancestry. Points are colored by self-reported ancestry. Circled points indicate the 117 individuals defined as admixed (117AX). b A subset of GTEx v8 tissues has an 117AX sample size of at least 30. The seven tissues selected for cis-eQTL mapping in 117AX are colored and shown in bold. c LA tracts collapse consecutive variants on a single parental chromosome with the same ancestry assignment into contiguous haplotype blocks. The fine spatial resolution of local ancestry contrasts with the global ancestry proportions indicated in the legend. Haplotypes (columns) are paired by individuals; rows are autosomal chromosomes. Individuals are sorted from left to right by decreasing proportions of European admixture. d gPCs are highly correlated with global ancestry proportions averaged from genome-wide local ancestry. e Local (or global) ancestry explains a fraction of variance in residual gene expression after correcting for global (or local) ancestry. Local ancestry is defined as the local ancestry at the transcription start site of each gene; global ancestry is the first five gPCs. Points are colored by tissue; colors correspond with b. Subc., subcutaneous; NSE, not sun-exposed; VE, variance explained; LA, local ancestry; GA, global ancestry

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