The Trans-Ancestral Genomic Architecture of Glycemic Traits

Glycemic traits are used to diagnose and monitor type 2 diabetes, and cardiometabolic health. To 462 date, most genetic studies of glycemic traits have focused on individuals of European ancestry. Here, 463 we aggregated genome-wide association studies in up to 281,416 individuals without diabetes (30% 464 non-European ancestry) with fasting glucose, 2h-glucose post-challenge, glycated hemoglobin, and 465 fasting insulin data. Trans-ancestry and single-ancestry meta-analyses identified 242 loci (99 novel; 466 P<5x10-8), 80% with no significant evidence of between-ancestry heterogeneity. Analyses restricted 467 to European ancestry individuals with equivalent sample size would have led to 24 fewer new loci. 468 Compared to single-ancestry, equivalent sized trans-ancestry fine-mapping reduced the number of 469 estimated variants in 99% credible sets by a median of 37.5%. Genomic feature, gene-expression 470 and gene-set analyses revealed distinct biological signatures for each trait, highlighting different 471 underlying biological pathways. Our results increase understanding of diabetes pathophysiology by 472 use of trans-ancestry studies for improved power and resolution