Wild-type His1 gene in the context of a histone gene repeat tandem array.
Wild-type His2B gene in the context of a histone gene repeat tandem array.
Wild-type His3 gene in the context of a histone gene repeat tandem array.
Mutated His4 gene (amino acid replacement K20A) in the context of a histone gene repeat unit.
A tandem array containing 12 copies of a mutated histone gene repeat unit (each repeat contains one copy of mutant His4 and wild type copies of His1, His2A, His2B and His3).