Examples of incompatible and compatible genetic backgrounds. We assume that two haplotypes have been taken from the postreproduction population; their genetic backgrounds are denoted by

^{(1)} and

^{(2)}, respectively. The thick and thin lines in a haplotype indicate regions with and without deleterious mutations, respectively. The genetic backgrounds are

^{(1)} = {

**x** = (0,

*x*, 1),

**y** = (1, 0)} and

^{(2)} = {

**x** = (0,

*x*, 1),

**y** = (0, 1)} in A and

^{(1)} = {

**x** = (0,

*y*, 1),

**y** = (1, 0)},

^{(2)} = {

**x** = (0,

*x*, 1),

**y** = (0, 1)}, and

^{(A)} = {

**x** = (0,

*x*,

*y*, 1),

**y** = (0, 1, 0)} in B. As explained in the text,

^{(1)} and

^{(2)} in A are incompatible, and consequently, the two haplotypes cannot be born to the same parent in the previous generation. In contrast,

^{(1)} and

^{(2)} in B are compatible. The probability that the two descendant haplotypes coalesce into a common parent is given by Equation 11, where

^{(A)} is the genetic background of the parent.

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