the other surrogate parents. Indeed, the fact that any surrogate relatives, regardless of Erdös distance, could contribute to the phasing of each other also means that for individuals belonging to the main cluster in the haplotype-sharing graph, even a single genotyping error for one of the SNPs can often be detected because of resulting incompatibilities. While this means that the data have extraordinary power in the detection of irregularities, the challenge is in the determination of what is the cause of an incompatibility. Incompatibilities could result from one of the following: Simple genotyping errors.Misinterpretation of the data due to the presence of structural mutations such as deletions and duplications in some of the individuals. While this could be considered as a form of genotyping errors, the difference from I is that these errors are systematic rather than random, and in some cases may affect the calling of a long sequence of SNPs.A putative surrogate parent does not actually share a haplotype with the proband at the region at all, or more frequently the surrogate parent only shares a haplotype with the proband for part of the region (some recombination event has cut-off the IBD sharing at a certain location, but
