Practice question

3 prime RACE exploits the natural poly-adenine tail present at the 3 prime end of most eukaryotic messenger RNAs. First-strand complementary DNA synthesis uses an oligo-dT primer that includes an adapter sequence, anchoring at the poly-A junction. The second strand is not synthesized by random hexamers alone, which would generate non-specific products. Instead, amplification utilizes the adapter-tagged oligo-dT as reverse primer combined with a forward gene-specific primer located within known exonic sequence. This strategy ensures selective enrichment of the downstream region between known sequence and poly-A tail terminus.