THREE-QUARTER SIBS
In the main monograph, it was shown that 3/4 sibs (R = 0.375) result when either a person marries his/her former spouse's full sib or his/her full sib's former spouse. The equivalent of 3/4 sibs can also occur when a person married his/her father-in-law. Mother-in-law, son-in-law or daughter-in-law, after the death of his/her spouse or partner. This can leave two sets of children which have a relationship of 0.375 between the two sets. The legality of marrying in-laws is also covered in the main monograph.
Example 1
Figure 87 Marriage to Father-in-law
A♂ = Father-in-law
B♀ = Mother-in-law
C♀ = Female proband (subject)
D♂ = Husband
E♂ and F♂ are 3/4 sibs i.e. REF - 0.375
* Subjects are printed in red.
Example 2
Figure 88 Marriage to Mother-in-law
A♀ = Mother-in-law
B♂ = Father-in-law
C♂ = Male proband
D♂ = Wife
E♂ and F♂ are 3/4 sibs i.e. REF - 0.375
* Subjects are printed in red.
Example 3
Figure 89 Marriage to Son-in-law
A♀ = Female proband
B♂ = Husband
C♂ = Son-in-law
D♀ = Daughter
E♂ and F♂ are 3/4 sibs i.e. REF - 0.375
* Subjects are printed in red.
Example 4
Figure 90 Marriage to Daughter-in-law
A♂ = Male proband
B♀ = Wife
C♀ = Daughter-in-law
D♂ = Son
E♂ and F♂ are 3/4 sibs i.e. REF - 0.375
* Subjects are printed in red.