Two different mutations are identified in a haploid strain of yeast. The first prevents the synthesis of adenine by a nonsense mutation of the ade-1 gene. In this mutation, a base-pair substitution changes a tryptophan codon () to a stop codon (). The second affects one of several duplicate genes. This base-pair substitution mutation changes the anticodon sequence of a from 3'- - 5' to 3'- - 5'.
Is the mutation in ade1 considered to be a forward mutation or a reversion?
Is the mutation in the tRNAtrp considered to be a forward mutation or a reversion?
Assuming there are no other mutations in the genome, will this double-mutant yeast strain be able to grow on minimal medium?