Genetic Engineering

What is genetic engineering?

• Application of molecular genetics for practical purposes

• Used to– identify genes for

specific traits – to transfer genes from

one organism to another

– to cure diseases

Restriction Enzymes

• Bacterial enzymes that cut DNA molecules into pieces

• Each enzyme recognizes specific sequences of nucleotides and cut at that site

• Can be used to isolate a specific gene

Sticky Ends

• The “tails” of DNA that are created when restriction enzymes cut DNA

• These sticky ends can bind to other sticky ends

Cloning Vectors• A carrier that is used to clone a gene

• Also used to transfer a gene from one organism to another

• PLASMIDS & Liposomes are an example

Plasmids

• A ring of DNA that is inside of bacteria – Different from their main DNA

• Steps for gene-transfer – Plasmid is removed from bacteria cell (host cell)– Plasmid is cut with restriction enzymes– A gene is inserted into the plasmid– Plasmid is returned to the cell– When cell replicates it clones the gene– The bacteria then infects other cells, giving them the

gene (bacteria cell is called a transgenic organism)

You can add a gene or cut out a gene

Recombinant DNA• The combination of two or more pieces of DNA

• End result is that host cell transcribes the gene as if it was it’s own DNA

DNA Fingerprinting

• A pattern of bands made up of specific fragments from an individuals DNA

• Uses– Identify the suspect of a

crime– Determine if 2 people are

related– Compare relationship

between 2 species

Creating DNA Fingerprints (RFLP Analysis)• Extract DNA (blood/tissue)• Cut DNA into fragments using restriction enzymes• Separate fragments using gel electrophoresis

– By SIZE

• Add radioactive probes complementary to DNA of interest• Expose to photographic film• Analyze results

Polymerase Chain Reaction (PCR)

• Used to make lots of copies of DNA quickly

• Good for when we only have a small amount of DNA to begin with