Changing the Living World & Manipulating DNA

Selective Breeding Uses naturally occurring genetic variation in plants, animals, and other organisms Breed specific individuals Pass on desired traits Naturally occurring genetic variation Desired traits

Selective Breeding

Hybridization Crossing different species to bring together the best of both organisms. Hybrids are often hardier than either of the parents. Why might this be? Different species to

Genetic Engineering Altering the genetic code of an organism. How do we do this? 1. DNA extraction 2. Cut the DNA 3. Separate out genes Genetic code What are the tools of molecular biology? DNA extraction Cutting the DNA Separating out genes Cut and paste segments of DNA – recombinant DNA is formed

Genetic Engineering How do we change a DNA sequence? Cut and paste segments of DNA Recombinant DNA is formed Genetic code What are the tools of molecular biology? DNA extraction Cutting the DNA Separating out genes Cut and paste segments of DNA – recombinant DNA is formed

Genetic Engineering How do we get the recombinant DNA back into a living cell? Bacteria can be transformed using recombinant DNA. New DNA is joined with the plasmid of the bacteria cell. Plasmid = small circular DNA Transformation transformed Plasmid Small, circular DNA molecule

Transformation

Transformation We use this process to: Insert desired genes/traits When organisms contain genes from another species, they are called: Transgenic organisms or genetically modified organisms Insert desired genes/traits Transgenic organisms or genetically modified organisms

Transgenic Organisms This is what we mean when we say a plant (like the ones we might eat or buy) has been genetically engineering or modified (GMOs)

Transgenic Organisms

Cloning A clone is a genetically identical cell produced from a single cell. Cloned colonies of bacteria are simple to grow….but more complex organisms are a much bigger challenge! First complex species cloned: In 1997... Wilmut cloned a sheep named Dolly… Genetically identical cell produced from a single cell. In 1997, Wilmut cloned a sheep named Dolly…

Cloning Dolly… Potential application of cloning: Saving endangered species Making copies of transgenic organisms

Gene Therapy An absent or faulty gene is replaced by a normal, working gene Viruses are often used because they have the ability to enter a cell’s DNA. Gene … normal, working gene

Gene Therapy How does this work? 1. The virus is modified so that it cannot cause disease. 2. A DNA fragment with the replacement gene is spliced to the viral DNA. 3. The patient is infected with the modified viruses How Does This Work? The virus is modified so that it cannot cause disease. A DNA fragment with the replacement gene is spliced to the viral DNA. The patient is infected with the modified viruses

Gene Therapy-Considerations Unfortunately, these experiments have not been very successful. Gene therapy remains a high-risk, experimental procedure. Ethical considerations??