Table 2:

Observed Allele Frequencies

Gene	SNP ID	Minor-Allele Homozygote	Heterozygous	Major-Allele Homozygote
OPRM1
	rs1799971	---	14.3% (AG)	85.7% (AA)
	rs6848893	---	19.0% (CT)	81.0% (TT)
OPRD1
	rs10753331	19.0% (AA)	33.3% (AG)	47.7% (GG)
	rs2234918	28.6% (TT)	33.3% (CT)	38.1% (CC)
	rs581111*	19.0% (TT)	28.6% (CT)	47.6% (CC)
	rs678849	33.3% (TT)	23.8% (CT)	42.9% (CC)
OPRK1
	rs6473797	23.8% (TT)	38.1% (CT)	38.1% (CC)
	rs963549	19.0% (TT)	28.6% (CT)	52.4% (CC)
COMT
	rs165599	23.8% (AA)	38.1% (AG)	38.1% (GG)
	rs4680	14.3% (AA)	61.9% (AG)	23.8% (GG)
	rs737865	4.80% (CC)	23.8% (CT)	71.4% (TT)

^*Genotype missing for one participant.