Phylogenetic Quantification of Intra-tumour Heterogeneity
Figure 2
Parental alleles are phased using context-free grammars.
A) Allelic phasing is achieved by choosing consecutive segments from either the major or minor allele which minimise the pairwise distance between profiles. B) The set of all possible phasing choices is modelled by a context-free grammar. In this representation, the order of the regions' copy-number values on the second allele is reversed, in order to match the inside-out parsing scheme of CFGs. That way every possible parse tree of the grammar describes one possible phasing.