Table 1 

Frequency and disease risk of 5 classes of genotypes under the model. 

Class 
Susceptible homozygotes 
Heterozygote of susceptible alleles 
Heterozygote with one R and one S allele 
Heterozygote of resistant alleles 
Resistant homozygotes 


Genotype 
S_{i}S_{i} 
S_{i}S_{i}, i ≠ j 
R_{i}S_{j} 
R_{i}R_{j}, i ≠ j 
R_{i}R_{i} 
Frequency 
Θ 
q^{2 } Θ 
2 pq 
p^{2 } Π 
Π 
Probability of Favorable Outcome 
x 
ax 
bx 
cx 
dx 


Notation: Frequency of allele S_{i }is q_{i}; frequency of allele R_{i }is p_{i}. p = p_{i}; q = q_{i }= 1  p; ; . The subscripts of R alleles and the subscripts of the S alleles are unrelated. 

Lipsitch et al. BMC Medical Genetics 2003 4:2 doi:10.1186/1471235042 