Which sequence represents a mutated gene?

In genetics, a mutated gene refers to a sequence of nucleotides that differs from the typical or reference sequence due to a change, addition, or deletion of nucleotide bases that alters the genetic information.

The correct sequence is identified as mutated because it contains a change in the arrangement or identity of nucleotides when compared with a standard reference, particularly focusing on the presence of accidental substitutions. In this context, examining the sequences, option B has a notable rearrangement where the codons are altered.

For example, the transition of “GGC” to “ACC” and the switch of "AAA" to "GAA" results in different potential amino acids that can be translated, thus affecting the encoded protein's structure or function. This disruption reflects the essence of a mutation, which can lead to changes in phenotypes or biological functions.

Understanding the context of each sequence and recognizing the patterns of nucleotide changes is essential in identifying mutations, which is why option B illustrates a clear deviation from what we would classify as a typical gene sequence.