Genomic mammalian DNA cannot be expressed directly using bacterial expression vectors because mammalian genomic DNA contains introns, which the bacterial cell cannot excise. Complementary DNA, or CDNA, enables scientists to express mammalian DNA from a bacterial plasmid. Place the sentences below into the correct order to describe the formation of double-stranded cDNA. You will only use five of the seven sentences.
DNA to be cloned
1. The DNA to be cloned is removed from the mammalian cell and incubated with reverse transcriptase.
2.Reverse transcriptase, provided with a primer, synthesizes a strand of cDNA without introns.
3. Mature mammalian mRNA is isolated.
4. A complementary DNA strand is synthesized forming a double-stranded cDNA molecule.
5. The mRNA is hydrolyzed by raising the pH.
Double-stranded DNA
6. A primer site is created on the single-stranded.
7. DNA mRNA is hydrolyzed by lowering the pH.