Description of the hsphase algorithm for eight SNPs and three half-sibs. A Genotype matrix (0, 2 are homozygotes, 1 are heterozygotes), blue genotypes highlight informative loci (opposing homozygotes – heterozygous in the sire, homozygous in the offspring). B Identification of the paternal origin of strands and recombination events (x) by using the Forward Memory Vector. (P and M are arbitrarily assigned paternal and maternal strands of the sire). C Final result of blocking after filling in the loci for which the sire strand could be determined. P and M refer to the two strands in the sire; - (dash) is used for unknown strand. D Imputation and phasing of the sire by combining the original offspring genotypes and the block structure.