Mutated His4 gene in the context of a histone gene repeat unit; contains a R19H amino acid replacement.
Wild-type His1 gene in the context of a histone gene repeat unit.
Wild-type His2A gene in the context of a histone gene repeat unit.
Wild-type His2B gene in the context of a histone gene repeat unit.
Wild-type His3 gene in the context of a histone gene repeat unit.