A variation generation model based on gene conversion. (a) At generation '0', a (reference) native DNA sequence, gi,0, encodes a amino acid sequence, Agi,0. The mutation of nucleotides generate a new sequence, gi,1, at generation '1', which encodes a mutated amino acid sequence, Agi,1. This is achieved when a donor sequence, gk,0, is randomly selected to provide a sub-sequence to gi,0. The resulting mutated sequence at generation '0' encodes Agi,1. The variability of a gene i, gi,j, at generation j, is estimated by measuring the difference between Agi,0and Agi,j. (b) A more detailed graphical illustration (at the DNA level) of the biological gene conversion model based on SDSA homologous recombination (adapted from ), which is computationally approximated by model summarised in (a).