Which mutation arises from the loss of one or more base pairs in the DNA sequence?

Which mutation arises from the loss of one or more base pairs in the DNA sequence?

• A. Point mutation
• B. Trinucleotide repeat disease
• C. Deletion mutation
• D. Autosomal dominant disease

Answer: (C)

A deletion mutation involves the loss of one or more nucleotide base pairs from the DNA sequence. This exactly matches the description of “loss of one or more base pairs,” and it can range from a single base pair to large chunks removed. When bases are deleted, the reading frame of the gene can be shifted (if the number removed isn’t a multiple of three), changing every downstream codon and usually producing a nonfunctional protein. Even small deletions can remove essential amino acids or regulatory elements, altering protein function or stability. In contrast, a point mutation is a substitution of a single nucleotide, not a loss of nucleotides. A trinucleotide repeat disease results from expansion of three-base repeats, not a deletion. An autosomal dominant disease refers to a pattern of inheritance rather than a mutation type.

A deletion mutation involves the loss of one or more nucleotide base pairs from the DNA sequence. This exactly matches the description of “loss of one or more base pairs,” and it can range from a single base pair to large chunks removed. When bases are deleted, the reading frame of the gene can be shifted (if the number removed isn’t a multiple of three), changing every downstream codon and usually producing a nonfunctional protein. Even small deletions can remove essential amino acids or regulatory elements, altering protein function or stability.

In contrast, a point mutation is a substitution of a single nucleotide, not a loss of nucleotides. A trinucleotide repeat disease results from expansion of three-base repeats, not a deletion. An autosomal dominant disease refers to a pattern of inheritance rather than a mutation type.