(GP1, GP2)(GS1, GS2) IBD status X  Statistic
(11, 12)     (11, 11) 0 IBD 
1 IBD                                                                         
2 IBD    
X0 = none
X1 = 3 – 2 = 1 
X2 = 2 – 1 = 1
(11, 12)     (11, 12)   0 IBD
1 IBD
2 IBD
X0 = 1 – 1 = 0
X1= 2 – 2 = 0
X2 = none
(11, 12)     (12, 12)   0 IBD
1 IBD
2 IBD
X0 = none
X1= 1 – 2 = -1
X2 = 1 – 2 = -1
(12, 12)     (11, 11)   0 IBD 
1 IBD                                                                         
2 IBD    
X0 = none
X1= none
X2 = 2 – 0 = 2
(12, 12)     (11, 12)   0 IBD 
1 IBD                                                                         
2 IBD    
X0 = none
X1= 2 – 1 = 1
X1 = none
(12, 12)     (11, 22)   0 IBD 
1 IBD                                                                         
2 IBD    
X0 = 2 – 2 = 0
X1= none
X2 = none
(12, 12)     (12, 12)   0 IBD 
1 IBD                                                                         
2 IBD
X0 = 0 – 0 = 0
X1= 1 – 2 = -1   or  2 – 1 = 1
X1 = 1 – 1 = 0
(12, 12)     (12, 22)   0 IBD 
1 IBD                                                                         
2 IBD    
X0 = none
X1 = 1 – 2 = -1
X2 = none
(12, 12)     (22, 22)   0 IBD 
1 IBD                                                                         
2 IBD    
X0 = none
X1 = none
X2 = 0 – 2 = -2
(22, 12)     (22, 22)   0 IBD 
1 IBD                                                                         
2 IBD    
X0 = none
X1 = 0 – 1 = -1
X2 = 0 – 1 = -1
(22, 12)     (22, 12)   0 IBD 
1 IBD                                                                         
2 IBD    
X0 =1 – 1 = 0
X1 = 1 – 1 = 0
X2 = none
(22, 12)     (12, 12)   0 IBD 
1 IBD                                                                         
2 IBD    
X0 = none
X1 =1 – 0 = 1
X2 =1 – 0 = 1

Table 4: X Statistic in ASP family