Table 1 Summary of breeding outcomes at birth.

Maternal

Igf2r^+m/I565A ♀ × Igf2r^+m/+p ♂

Igf2r ^+m/+p

39

34.5

*P = NS

(11 litters, 5 pairs)

Igf2r ^{I565A/+ p}

30

34.5

Paternal

Igf2r^+m/+p ♀ × Igf2r^+m/I565A ♂

Igf2r ^+m/+p

25

27

*P = NS

(10 litters, 3 pairs)

Igf2r ^{+ m/I565A}

29

27

Homozygote

Igf2r^+m/I565A ♀ × Igf2r^+m/I565A ♂

Igf2r ^+m/+p

25

14.75

*P = 0.0006

X² = 14.97

Igf2r ^{+ m/I565A} or Igf2r ^{I565A/+ p}

30

29.5

(9 litters, 3 pairs)

Igf2r ^I565A/I565A

4

14.75