As detailed in the supplement, most common methods for estimating SNP heritability and genetic correlation either require modification or may not be suitable for use in multi-ancestry studies. Methods relying on relatedness estimation (e.g., genomic relatedness matrix restricted maximum likelihood; GREML) require estimation methods robust to population structure (Conomos et al., 2018; Thornton et al., 2012), and methods modelling LD (e.g., LD Score regression; LDSC) require either ancestry-matched reference panels or individual level data for LD calculations (Luo et al., 2018). Ancestry-matched reference panels, along with the large GWAS sample sizes required for robust estimation using these methods, may be especially challenging to acquire for studies in underrepresented or admixed groups.
