What is different between these 2 sequences? GGAATTCCTAGCAAT CCTTAAGGATCGTTA CTACGTGAGGAATTC GATGCACTCCTTAAG
Only order of bases! • The actual chemical nucleotides are the SAME, even though the blue is sequence from US (eukaryotes) and the green is from bacteria (prokaryotes)! • So, DNA in plants, bacteria and us is chemically the SAME!!! That means, bacteria can “read” our DNA! (transcribe & translate our genes!) • Because of this, we can put our genes (or plant genes) in bacteria- this is what Recombinant DNA technology does!
Tools of Recombinant DNA • Plasmid : a small circular DNA molecule that is not part of the bacterial chromosome; replicates independently • Restriction Enzyme: Molecular scissors that cut DNA at a specific nucleotide sequence • Ex.: EcoRI CATCGAATTCAC GTAGCTTAAGTG
Tools, cont. • DNA Ligase: An enzyme that joins 2 DNA fragments together (the “glue gun”). • Escherichia colistrains: Weakened strains of bacteria that are used to grow the plasmids. • Transformation: Process used to put the plasmid back into the bacteria
Animations: • http://webapps.css.udel.edu/biotech/rDNA.html
Why put a human or plant gene in bacteria? • Make lots of copies of the sequence • More of an issue before the human genome project • Mutate or change 1 human gene separate from the other 28,000 genes…. • Make lots of a human protein cheap & easily! (ex. is human insulin) • http://webapps.css.udel.edu/biotech/rDNA.html