Table 1.- Variants (SNPs) included in the PRS calculation
(Disease/Trait: Type_I_diabetes)
rsID	Risk allele	Effect size
rs6679677	A	0.637
rs12708716	A	0.207
rs17696736	G	0.199
rs6897932	C	0.113
Effect size: LN(OR)

Table 2.- PRS Score distribution among populations and regions
(Disease/Trait: Type_I_diabetes)
	count	mean	sd	se	lower.ci	upper.ci
Pyrenean regions
WEST	168	0.091	0.047	0.004	0.084	0.098
SOUTH	83	0.085	0.036	0.004	0.077	0.093
EAST	146	0.087	0.044	0.004	0.080	0.095
Populations
IBS	107	0.088	0.040	0.004	0.081	0.096
PIR	397	0.088	0.043	0.002	0.084	0.093

Table 3.- Pairwise t-test for PRS score among populations and regions
(Disease/Trait: Type_I_diabetes)
group1	group2	n1	n2	p	p.signif	p.adj	p.adj.signif
IBS	PIR	107	397	0.967	ns	1	ns
IBS	WEST	107	168	0.583	ns	1	ns
IBS	SOUTH	107	83	0.588	ns	1	ns
IBS	EAST	107	146	0.869	ns	1	ns
WEST	SOUTH	168	83	0.273	ns	1	ns
WEST	EAST	168	146	0.432	ns	1	ns
SOUTH	EAST	83	146	0.672	ns	1	ns
* p < .05, ** p < .01, *** p < .001

Table 4.- Chi-square test comparison of percentile counts on Pyrenean regions compared to Iberian peninsula population
(Disease/Trait: Type_I_diabetes)
Percentile rank	PIR				WEST				SOUTH				EAST
	adj.std.val	p.value	sig.val		adj.std.val	p.value	sig.val		adj.std.val	p.value	sig.val		adj.std.val	p.value	sig.val
pct95	0.370	0.711	.	white	1.340	0.180	.	white	0.370	0.711	.	white	−0.130	0.897	.	white
pct75.95	−2.190	0.029	*		−1.000	0.317	.	white	−2.190	0.029	*		−0.450	0.653	.	white
pct50.75	1.190	0.234	.	white	−1.370	0.171	.	white	1.190	0.234	.	white	−0.730	0.465	.	white
pct25.50	1.310	0.190	.	white	1.970	0.049	*		1.310	0.190	.	white	1.070	0.285	.	white
pct25	−0.860	0.390	.	white	−0.500	0.617	.	white	−0.860	0.390	.	white	0.170	0.865	.	white
adj.std.val: Adjusted standardized residuals value; p.value: P value; sig.val: statistical significance, * p < .05, ** p < .01, *** p < .001; red dash to bottom: lower counts than reference; green dash to up: upper counts than reference