What does the "c." denote in nucleotide change notation?

The designation "c." in nucleotide change notation stands for "coding sequence." This notation is used in molecular genetics to specify the location of a mutation or polymorphism within a gene's coding region. When a nucleotide change is described, it often follows this "c." prefix to indicate that the change impacts the sequence that is translated into protein, distinguishing it from changes in non-coding regions. This system allows for a standardized way to communicate precise mutations within the coding region of DNA.

The other terms do not accurately represent the purpose of the "c." notation. While complementary strands and cellular localization are important concepts in genetics, they do not relate directly to the standard notation for indicating changes within coding sequences. Similarly, conservative substitutions refer to types of amino acid changes rather than the notation used for specifying nucleotide alterations.