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Table 5 Comparison of exact and IBS methods in a particular case

From: Inferring relationships between pairs of individuals from locus heterozygosities

Genotype data

Exact calculation

IBS method

Ratio LR1/LR2

Marker

Sib1

Sib2

Genotype combination (1)

Allele frequencies (2)

Likelihood ratio (3)

Shared alleles

H (4)

Likelihood ratio (5)

 

CSF1PO

9–13

9–13

4

p9 = 0.044

p13 = 0.062

50.93

2

 

3.52

14.5

FGA

20–24.2

20–24.2

4

p20 = 0.156

p24.2 = 0.009

103.97

2

 

9.78

10.6

FES

12–13

12–13

4

p12 = 0.266

p13 = 0.047

13.38

2

 

2.94

4.6

F13A1

5–5

5–5

1

p5 = 0.184

 

10.32

2

 

3.83

2.7

D19S253

8–12

12–12

2

p12 = 0.369

 

0.93

1

0.760

0.35

2.7

F13B

6–8

6–10

6

p6 = 0.080

 

1.81

1

 

0.86

2.1

LPL

10–12

10–10

2

p10 = 0.275

 

1.16

1

0.723

0.89

1.3

TH01

9.3–9.3

9–9.3

2

p9.3 = 0.241

 

1.29

1

 

1.02

1.3

D18S51

13–19

14–17

7

  

0.25

0

 

0.25

1.0

D8S1179

13–15

13–15

4

p13 = 0.344

p15 = 0.116

4.82

2

 

6.07

0.8

TPOX

8–11

8–10

6

p8 = 0.512

 

0.49

1

 

0.78

0.6

VWA

17–18

17–18

4

p17 = 0.275

p18 = 0.206

3.52

2

 

5.71

0.6

D21S11

63–67

63–65

6

p63 = 0.244

 

0.76

1

 

1.17

0.6

Cumulative log(LR)

     

6.47

  

2.92

 

Probability

     

>99.999%

  

99.9%

 
  1. Calculations applied to the most discordant pair from Fig. 2 are fully displayed. (1)from Table 1A; (2)calculated from full-sib sample data; (3)FS rather than NR, computed using formulas from Table 1A; (4)computed from sample data; (5)FS rather than NR, computed from values in Table 3 or applying formulas from Table 2 to the displayed H values.