What happens when a purine is changed to a pyrimidine in a DNA sequence?

When a purine is changed to a pyrimidine in a DNA sequence, it can lead to an amino acid change because both purines (adenine and guanine) and pyrimidines (cytosine, thymine, and uracil) are components of codons, which are sequences of three nucleotides that code for specific amino acids during protein synthesis.

The alteration from a purine to a pyrimidine changes the identity of the nucleotide in the specific codon that is being transcribed and subsequently translated. This can result in a different codon being recognized, which may code for a different amino acid than originally intended. Depending on the specific codon affected by this substitution, it could alter the protein's structure and function, potentially leading to changes in biological activity.

While there are scenarios under which this change might not affect the resulting protein (such as if a different codon still codes for the same amino acid), the fundamental nature of the change (from purine to pyrimidine) creates the possibility of different amino acids being incorporated during translation, ultimately leading to potential functional effects on the protein.

Additionally, it's important to clarify that the other options do not accurately capture the typical outcomes of such a nucleotide substitution. A