TWe need to determine the shape of the tree if we are to decipher the history and ancestry of mutations, but this shape is a mathematical abstraction. If we wish to obtain an image of ancestral genealogies with a useful degree of precision, we need an algebraic description of haplotype decay for any possible graph representing the ancestry of a given variant.

Density probability for a two node-tree as a function of a number of generations (n , 0-200) and a branching point (x, 0-1).

The definition of haplotype blocks as physical entities, with clear borders, as for objects in the physical world, results in an apparent simplification. However, this simplification is not really helpful, because the unnecessary reduction of complexity may make it impossible to derive meaningful patterns.