Dna cloning: want to study a particular human gene, present in 2 copies in a cell, need much more dna to work with, use bacterial ability to carry plasmid dna molecules, bacteria replicate plasmid and divide. Restricting enzymes: can also use them to cut and paste dna, 2 pieces of dna cut with the same re can be pasted together, complementary sticky ends, ligase seals nick, recombinant dna, 1000"s of re"s. Dna probe: probe is complementary to gene of interest labelled with a marker. Pcr: producing dna by cloning is time intensive, multiple steps, bacteria, polymerase chain reaction is much quicker. Pcr background: second revolution in genetics, first is restriction enzymes, kary mullis (1984, 1993 nobel prize in chemistry, based on thermocycling, denaturation, annealing, elongation. Initially polymerase added every cycle: high temp in denaturation stage denatures proteins, taq polymerase, from thermus aquaticus a thermophilic bacteria, taq polymerase does not denature at 94 c, adds dntps 5" 3" (~1000/min)
