Adjective
unmutated (not comparable)
Not mutated.
Cells with heterozygous mutations (one good copy of gene and one mutated copy) may function normally with the unmutated copy until the good copy has been spontaneously somatically mutated. Source: Internet
Umlaut is conspicuous when it occurs in one of such a pair of forms, but there are many mutated words without an unmutated parallel form. Source: Internet