Fig. 4From: Transition-transversion encoding and genetic relationship metric in ReliefF feature selection improves pathway enrichment in GWASTwo-dimensional transition/transversion genotype encoding. Genotypes are represented as vectors on a unit circle and their similarity is the cos2θ of their angular separation. Transversion genotype vectors (red) are more expanded than transitions (by π/4) to account for the alleles (A and a) coming from different nucleotide families (one purine and one pyrimidine). Transition genotype vectors (blue) are more compressed together (by π/6) to account for the alleles (A and a) coming from the same nucleotide family (both purine or both pyrimidine). For both transition and transversion SNPs, we center the heterozygous genotype vector at π/4Back to article page