Final answer:
Deletion mutation 9 fails to complement mutation 4 because it likely affects the same gene. Insertions or deletions of a nucleotide can cause a frameshift mutation, which changes the reading frame resulting in a nonfunctional protein, whereas missense and nonsense mutations involve changes in amino acids or premature stop codons, respectively.
This is because mutations 1, 3, 5, 7, and 8 are not options provided in the question and hence are presumed to be correct complements, leaving mutation 4 as the non-complementing option.
Step-by-step explanation:
A deletion mutation that fails to complement another mutation indicates that they affect the same gene or functional region. Complementation refers to the phenomenon where two different mutations in the heterozygous state result in a wild-type phenotype if they are in different genes. If no wild-type phenotype is observed, the mutations are said to be in the same gene (or fail to complement). Therefore, if deletion mutation designated 9 fails to complement mutations 1, 3, 5, 7, and 8, it likely affects the same gene or functional region that one of these mutations affects. Specifically, the mutation that deletion mutation 9 fails to complement is mutation 4.
Focusing on the different types of mutations and their effects, an insertion or deletion of a single nucleotide can cause a frameshift mutation because it changes the reading frame of the codons in the mRNA. A frameshift mutation often results in a completely different and usually nonfunctional protein because every amino acid downstream of the mutation is different. In contrast, a misense mutation results from a single nucleotide change that leads to the substitution of a different amino acid, which can affect the function of the protein to varying degrees. A nonsense mutation is a point mutation that results in a premature stop codon, leading to a truncated and typically nonfunctional protein.