At this point, we may want to ask: why not combine ``peeling'' (tree forward-backward) with the HMM forward-backward along loci and make the calculation linear in the number of loci times number of individuals in the pedigree? The answer is that it may be possible if we solve the storage problem and work through individual-allele combinations in a suitable manner. The allele recoding techniques presented in the next section may provide a solution to the problem.