Presentation on theme: "Genetic Engineering Modifying an organism’s genotype by introducing genes from another organism (often another species) This "autoluminograph" of a glowing."— Presentation transcript:
1 Genetic EngineeringModifying an organism’s genotype by introducing genes from another organism (often another species)This "autoluminograph" of a glowing transgenic tobacco plant bearing the luciferase gene of a firefly was first done in 1986
2 What’s Recombinant DNA? Recombinant DNA – Refers to the molecule formed by joining different biological sourcesTransgenic/Genetically Modified Organism - An organism whose genome has been modified by introducing novel DNA“Flavr Savr” first sold in 1990s
3 How can recombinant DNA be used? Improved crops (drought & heat resistance)Improved livestockAnimals with human genes for researchPrevention and cure of genetic diseasesProduction of pharmaceuticalsGerm line and somatic gene therapyTransgenic art (alba = part bunny, part jelly fish)
5 MAKING RECOMBINANT DNA MOLECULES: Cut large DNA molecules into smaller pieces with the use of restriction enzymesThese enzymes recognize specific DNA sequences that are 4-6 nucleotides in length.The enzyme is used by bacteria to destroy DNA of invading viruses, but genetic engineers use the enzyme to cut and paste DNA molecules from different sources.
6 DNA TECHNOLOGY VOCABSPLICING- cutting the DNA of a gene to add new base pairsVECTOR- transport vehicle which carries the desired gene into the host cellPLASMID- a small circular DNA molecule found in bacteria (separate from the main bacterial chromosome)RESTRICTION ENZYME- a special DNA-cutting enzyme that is found in bacteriaDNase- eukaryotic DNA-digesting enzymesDNA LIGASE- an enzyme that seals the gaps in the DNADNA CLONING- making many copies of DNA (amplification) through the use of a host bacterial cellRESTRICTION FRAGMENTS- Pieces of DNA of varying lengthsGEL ELECTROPHORESIS- DNA fragments move through a porous gel in response to an electric current (the smaller the fragment the faster it moves) DNA PROBE- a single-stranded DNA fragment that possesses a particular sequence that is complementary to the fragment being sought. Sort of like a guided missile.
7 Restriction Maps:A restriction map is a description of the restriction cleavage sites within a piece of DNA
8 Restriction enzymes generate a “staggered cut” in the DNA This leaves short, single-stranded tails that act as “sticky ends” that can bind with a complementary single-stranded tail on another DNA molecule.since the restriction enzyme always cuts a DNA molecule at the same site in a sequence, it creates the same sticky ends regardless of the organism that donated the DNA.
9 Sticky ends from human chromosomes readily adhere to the complementary single-stranded tails of the bacterial plasmid that has been cut with the same enzyme.When mixed together, the complementary sticky ends join the isolated human gene segment to the plasmid.4. DNA ligase acts as the tape to bond the DNA fragments together.
10 The Recombinant DNA is amplified by DNA cloning. Place recombinant DNA molecule in a host bacterial cell to replicate. Then recombinant DNA is purified and used in other procedures.
11 6. If manufacturing the proteins, mammalian cells (cultured in vitro) can also serve as hosts for human genes.SOME EXAMPLESinsulin for diabeticsfactor VIII for males suffering from hemophilia Ahuman growth hormone (GH)granulocyte-macrophage colony-stimulating factor (GM-CSF) for stimulating the bone marrow after a bone marrow transplantangiostatin and endostatin for trials as anti-cancer drugshepatitis B surface antigen (HBsAg) to vaccinate against the hepatitis B virus