“Amazing Schemes Within Your Genes” Genetic Engineering “Amazing Schemes Within Your Genes”

What is genetic engineering? Moving small pieces of DNA from one organism into another organism

What is recombinant DNA technology? Same thing as genetic engineering Recombinant DNA – made by connecting (splicing) fragments of DNA from different sources

How does recombinant DNA work? DNA is inserted into an organism Organism uses foreign DNA as if it were its own

What are these new things called? Transgenic organisms contain recombinant DNA (initial + “foreign”)

How do scientists move DNA (genes) to make transgenic organisms? Isolate source of foreign DNA to be inserted Join DNA with a vehicle that can transport it Transfer DNA (from chromosomes) into new host

How is DNA isolated? Restriction enzymes are used

What are restriction enzymes? Proteins that come from bacteria They recognize, bind to and cut DNA into smaller fragments at certain points >200 different enzymes Examples are: EcoRI, HinD III, Bam HI, Bgl II

Isolate source of DNA Ex: EcoRI – cuts between G and A whenever it sees CTTAAG A G G T C T T A A G C T A G C T C C A G A A T T C G A T C G

Isolate source of DNA Don’t cut straight through both DNA strands Cut is offset by a few bases “Sticky” ends are produced C T T A A G G A A T T C C T T A A G G A A T T C

Ex: AluI – cuts between C and G whenever it sees AGCT Isolate source of DNA Ex: AluI – cuts between C and G whenever it sees AGCT A G C T T C G A A G C T T C G A “Blunt” ends are produced

Isolate source of DNA Sticky Ends DNA can form circle because complementary bases OR DNA can pair with any other DNA fragment cut by the same enzyme (same bases exposed) = Recombinant DNA

REFRESHER: How do scientists move DNA (genes)? Isolate source of DNA Answer: through Restriction Enzymes Join DNA to a vehicle that can transport it Answer: ??? Transfer DNA (from chromosomes) into target cell

Join DNA to a transport vehicle Vector – means by which DNA from one organism gets to target/host cell

Types of Vectors Mechanical Micropipette inserted into cell Gene gun shoots tiny metal bullet coated w/ DNA Biological Virus Plasmid

What is a plasmid? A small ring of DNA found in bacteria, which only carries genes under extreme circumstances Both plasmid and foreign DNA are cleaved w/ same restriction enzyme They are spliced using a “glue” called a ligase (enzyme)

How do we know if foreign DNA has been successfully transferred? Host cell copies recombinant DNA and its own DNA Clones are created as host continues to divide (all w/ desired DNA) Foreign DNA codes for the production of a specific protein – test the cloned cells to see if they produce protein or not

And the final product is… Newly recombined DNA that undergoes mitosis, producing multiple copies of new DNA Bacteria is considered a good host because it reproduces quickly

Genetically Engineered