[Algorithm for calculating the probabilities of the identity of genes by descent in arbitrary pedigrees]

For an arbitrary locus (autosomal or X-linked), comprehensive enumeration of different variants of genes' identity by descent for two individuals is given. The algorithm for computation of probability of every variant is described for any two individuals in arbitrary pedigree. On the basis of the algorithm proposed, the problem of computation of Malecot's "coefficient de parente" and inbreeding coefficient is solved under sex-linked transmission. It has been also shown that the approach described is the most common method for solution of a problem of partitioning of covariances among relatives on genotypic components of the variance.