To identify potentially causative biological mechanisms for AD, we examined our scoring bins, ones defined by cumulative GWAS P-value thresholds, for discernible ontological patterns, including those comprised of alleles with small, statistically non-significant effects on disease risk. The permuted Fisher’s exact tests show that about 90% of the examined ontologies exhibit no significant evidence of gene enrichment (empirical P ≤ 0.05) for any of the twenty P-value thresholds for either population (Table S6), with the percentages slightly higher for the signaling pathways. Of the biological relationships that do show significant enrichment, approximately half are for single thresholds, with only a limited number displaying significance across three or more of the tested levels (n = 15 and 19 for EAs and AAs). From this latter group, the following four ontologies show evidence of significant enrichment in both population samples (in parentheses are the sizes of the ontologies after being matched against the gene coverage of population-specific GWAS data, along with the top empirical P-values observed for the various EA and AA gene lists, respectively): Maf transcription factors (n = 6 genes;
