Which change is the following process most likely to affect? Eukaryotic genes can contain thousands of nucleotides that define the sequence. Not all the nucleotides are actually used to code for corresponding RNA molecules. Genes are divided into introns and exons based on whether or not a region of DNA within a gene is transcribed into messenger RNA. A mutation in a eukaryotic cell is shown below. The mutation is located at the 5′ end of an intron.

Splicing

The correct answer is D. Introns are noncoding regions of RNA that are spliced out of mature mRNA. Almost all introns begin and end with 5 GUAG 3. A mutation in one of those nucleotides affects splicing. This type of mutation is one of those found in thalassemia Answer A is incorrect. Capping of the mRNA occurs at the 5 end as it is being transcribed. A mutation at the 5 end of an intron would not affect capping Answer B is incorrect. Hybridization is a process in which single-stranded DNA base-pairs with a complementary sequence. A mutation at the 5 end of an intron would not affect hybridization Answer C is incorrect. A poly(A) tail is added to the 3 end of RNA after transcription. Poly(A) polymerase uses ATP as a precursor for adding adenosine one at a time. A mutation at the 5 end of an intron would not affect polyadenylation Answer E is incorrect. Transcription of the DNA into RNA would not be affected by this mutation.