Asthma prevalence varies across populations, but it is unclear how much this is due to genetic factors. CGM PIs, Mark Daly, Alicia Martin, and colleagues report findings from a large-scale GWAS of asthma. In their meta-analysis of 22 biobanks spanning diverse ancestries, they uncovered 179 loci associated with asthma, including 49 novel ones, and observed consistent genetic effects across ancestries and biobanks, suggesting that genetic effects are unlikely to drive most prevalence differences. They also found genetic correlations between asthma subtypes and co-morbidities. The study’s increased ancestral diversity relative to previous analyses improved polygenic risk prediction in non-European populations.