Chapter 9 Biotechnology

DNA Extraction Why would we want to extract DNA? Use chemicals to break down cell membrane/wall and nucleus. The DNA is now free to be extracted DNA is sticky, and can be easily pulled out of a mixture. This is called “spooling” DNA

“Spooled” DNA Extracted DNA

Restriction Enzymes After DNA has been extracted, restriction enzymes are added Cut DNA at VERY SPECIFIC sites Specific nucleotide sequence Makes large DNA molecules more manageable and easier to study. Cuts it up into smaller sections.

Restriction enzymes

Gel electrophoresis An electrical current is used to separate a mixture of DNA fragments from each other. Fragments are sorted by size. The smaller the fragment, the further it moves. DNA moves towards positive end of gel. DNA is negatively charged because of the phosphate Positive and negative attract.

Gel Electrophoresis

DNA fingerprinting There is a 1 in 5.4million chance that someone could have the same DNA as you. What are some of the ways that we use DNA fingerprinting today?

Cloning A clone is a genetically identical copy of a gene or an organism Asexual Reproduction = 100% identical Example: Plants clone themselves Example: Bacteria and binary fission = split into 2 Example: Sea star re-growing lost limbs (regeneration)

Cloning A body cell is taken from a donor who is going to be cloned. An unfertilized egg is taken from another individual and the nucleus is removed. The nucleus of the body cell is fused with the unnucleated egg cell to create an embryo. The embryo is then stimulated to begin dividing. Embryo is implanted into a surrogate mother. Cloning “Dolly” 1997

Positive and negative of cloning. Cloning raises concerns. low success rate clones “imperfect” and less healthy than original animal decreased biodiversity organs for transplant into humans save endangered species Higher crop yields

Why aren't the cloned cats exactly identical? Environment has an affect on gene expression Why?

Transgenic/Recombinant DNA Plasmid – tiny rings of DNA found in bacteria A transgenic organism is one that has one or more genes from another organism inserted into its genome. Genetically modified organism (GMO)

Transgenic organisms: Genetically engineered crops Resistant to frost, disease and insects Smaller amount of pesticides needed to protect plant More and bigger plants produced

Human Genome Project Started in 1990 Research effort to sequence all of human DNA 46 chromosomes Over 3.3 billion nucleotides Mapping every gene location (loci) Conducted by scientists around the world

Gene Therapy The replacement of a defective or missing gene, or the replacement of a new gene, into a person’s genome to treat a disease. First successful gene therapy took place in 1990 Much of gene therapy is still experimental Researchers are studying many different methods to treat cancer Gene to stimulate persons immune system to attack cancer cells Insert “suicide” gene into cancer cells.