Fig. 1

Different patterns of linkage disequilibrium among seven VEGFA promoter SNPs in the four study groups: a control Han Chinese, b AMS patients, c control Tibetan Chinese, and d CMS patients. The degree of genetic linkage between the seven SNPs is estimated as r ² values where dark red color (r ² = 1) in the linkage disequilibrium pattern means that there exists strong pairwise linkage disequilibrium between adjacent SNPs and no color means that LD is weak or non-existent (r ² > 0). The SNPs are labeled by their nucleotide distance in base pairs from the transcription start site (TSS). The tagged (blue color) VEGFA-2578 SNP (rs699947) is furthest from the TSS