Figure 1
From: Direct maximum parsimony phylogeny reconstruction from genotype data

Phasing: computationally inferring genotypes from haplotypes. Although DNA sequences consist of four bases, single nucleotide polymorphisms (SNPs) are biallelic. Therefore, the sequence variation can be expressed using binary symbols. The observed genotype sequences consist of conflated combinations of two true haplotype sequences. Programs that computationally infer haplotypes attempt to minimize switch errors.