G6PD and G6PD deficiency: An evolutionary analysis based on a multiple alignment of amino acid (aa) sequences from 52 G6PD orthologs across 42 organisms revealed a correlation between aa replacements causing G6PD deficiency in humans and G6PD sequence conservation: two-thirds of such replacements affect highly and moderately conserved aas, and relatively few affect fully conserved aas and non-conserved aas, where they could be lethal, or presumably simply would not cause G6PD deficiency [11].