Kinship testing - An Introduction to Forensic Genetics - page 135

Table 11.1 The numerator and denominator that should be used when calculating a paternity
index are determined by the genotypes of the child ( G C ), mother ( G M )andtestedman( G TM ). The
alleles are represented by A , B , C and D where A = B = C = D
G C

G M G TM Numerator Denominator PI

1
p A

AA AA AA 1 p A

1
2 p A

AB

1

p A / 2

BC 0 p A 0

p A
2

1
p A

AB AA

1

/ 2

p A
2

1
2 p A

AB

1

/ 4

p A
2

1
2 p A

AC

1

/ 4

p A
2

BC 0 0

1
p B

AB AA BB 1 P B

1
2 p B

AB

1

/ 2

P B

1
2 p B

BC

1

P B / 2

CD 0 P B 0

P A + P B
2

1
p A + p B

AB AA

1

/ 2

P A + P B
2

1
p A + p B

AB

1

/ 2

P A + P B
2

1
2( p A + p B )

AC

1

/ 4

P A + P B
2

1
2( p A + p B )

BC

1

/ 4

P A + P B
2

CD 0 0

P B
2

1
p B

AC BB

1

/ 2

P B
2

1
2 p B

AB

1

/ 4

P B
2

1
2 p B

BC

1

/ 4

P B
2

1
2 p B

BD

1

/ 4

P B
2

CD 0 0

Based on Lucy [15], p. 174 and Evett and Weir [16], p. 168.