We require one last assumption in order to compute conditional
probabilities of inheritance vectors. Let 
denote the inheritance
vector of a sib-pair at the DS locus 
, 
, and 
.
Assumption G2. There is no segregation distortion,
i.e. for a sib-pair with multilocus parental genotype pg
and multilocus inheritance vector x at unlinked DS loci
In other words, there is no preferential transmission of certain alleles at the DS loci.