Consider the setting of Kruglyak and Lander and Kruglyak et al.
where we have a map of genetic markers and we wish to use the partial
genotype and IBD information from all markers to perform multipoint
linkage analysis at any point along the genome. Let m denote the
observed multipoint marker data.
The likelihood of the multipoint marker data, in terms of the IBD probabilities at a candidate locus has the general form
under Assumptions G1, G2, G3, G4 and the assumption that the candidate
locus is at a DS locus. Here 
is the inheritance
distribution at the candidate locus computed using a HMM (Lander-Green
Algorithm, ... more details later ...).
Sampling assumptions are the same as in the single marker situation.