Eukaryotic DNA Plasmid dna C 3′ add poly-dT tails Terminal deoxynucleotidyl transferase add poly-da tails A-A-A-G-G-GTTT3 G-G-G-T-T-T 5 5TTTC-CCAA-A-G-G-GTTT Annealing of fragments Ligation with DNA ligase TTTC-C-CA-A-A-G-G-G 3′ G-G-G-T-T-T C-C-C 5