Amino acid replacement: N?H.
Knock-in at the Atpα locus carrying a single substitution equivalent to N122H in the orthologous gene of the monarch butterfly (Danaus plexippus), as occurred in the mutational path of the monarch gene (though not alone) in its evolution of a specialized response to cardiac glycosides. This substitution is designated 'QAH', referring to overall Atpα genotype at three repeatedly changing amino acid sites (111, 119 and 122), where the starting genotype is 'QAN'. (Amino acid residues are numbered after the mature Sus scrofa protein, as in previous phylogenetic studies of Atp-alpha in insects.)