SUMMATIVE/PERFORMANCE TASK

• Genetic engineering


  • Method of modifying an organism's genetic structure using recombinant DNA technology
  • Humans have implicitly manipulated genomes by regulating breeding and choosing offspring with desirable characteristics
• Recombinant DNA technology


  DNA molecules are inserted into the host organism from two separate organisms to create novel genetic combinations important to science such as medicine and agriculture
• Paul Berg, a molecular biologist, shared the Nobel Prize in Chemistry in 1980 for his contributions to recombinant DNA technology
• rDNA technology


  Scientists use restriction enzymes from bacteria to cut DNA molecules only in particular locations
• Structure of plasmid DNA

  • Ori/Origin of Replication allows autonomous plasmid DNA replication
  • Antibiotic Resistance Gene helps bacteria survive and protects them against antibiotics
  • Restriction Site is used for the insertion of a gene of interest
  • Promoter region encourages transcription of target DNA
  • Selectable Marker enables selection of bacteria with the gene of interest
  • Gene of Interest is the particular gene being studied or manipulated in an experiment
• Stages of genetic engineering

  1. Identify the section of DNA containing the required gene from the source chromosome

  2. Extract the required gene

  3. Insert required gene into vector/bacterial plasmid

  4. Insert plasmid into the host cell

  5. Grow transformed cells to produce a GMO
• Genetically Modified Organism (GMO) is an organism whose genetic makeup has been modified using genetic engineering
• Genetically Modified Organism (GMO) is created in the laboratory to create a combination of genes that do not occur in nature or traditional crossbreeding techniques
• Applications of DNA technologies in Medicine

  • Human Insulin produced by Escherichia coli
  • Genetically Modified Human Growth Hormone (GH) available to address growth defects, especially pituitary dwarfism
• Applications of DNA technologies in Agriculture

  • Genetically Modified Tomato (CGN-89564-2) was the first genetically engineered crop product to be given a human consumption license
  • Pest Resistant Genetically Modified Crops have been modified to be toxic to certain insects using Bacillus thuringiensis (Bt)
• Applications of DNA Technologies

  • Agriculture
  • Pest Resistant Genetically Modified Crops
  • Genetically Modified Rice (Golden Rice)
• Pest-resistant GM crops


  • Genetically modified to be toxic to certain insects
  • Bacillus thuringiensis (Bt) bacteria produces Cry toxins toxic to some insects
  • In the Philippines, Bt corn was developed to be resistant to the Asian corn borer (Ostrinia furnacalis)
• Genetically Modified Rice (Golden Rice)


  • Named for its golden color caused by beta-carotene
• Mechanisms of Evolution


  1. Artificial selection

  2. Natural selection

  3. Gene flow

  4. Genetic drift

  5. Mutation

  6. Recombination
• Evolution consists of changes in the heritable traits of a population of organisms as successive generations replace one another
• Evolution happens in a population of organisms, not in individual organisms
• A population is a group of individuals of one species close enough to interbreed
• A population evolves due to changes in the gene pool
• Lamarck's Theory of Evolution involves the inheritance of acquired characteristics
• The theory of use and disuse of organs was proposed by Lamarck
• Artificial Selection


  • Identification of desirable traits in plants and animals by humans to enhance and perpetuate those traits in future generations
• Natural Selection


  • Mechanism through which living creature populations adapt and change, known as "survival of the fittest"
• Organisms with inherited characteristics suited to the environment have a better chance to survive and reproduce


  Known as survival of the fittest, leading to Descent with Modification
• Descent with Modification


  • Idea that species change over time, give rise to new species, and share a common ancestor
• Mutation


  • Genetic makeup alteration influencing the population's gene pool by changing DNA in one or more chromosomes
• Genetic Drift


  • Change in frequency of an existing gene variant in the population due to random chance, may reduce genetic variation
• Genetic mutation


  A change like the DNA in one or more chromosomes, resulting in new traits and genetic variation in a population
• Mechanisms of Evolution: Genetic drift

  Change in frequency of an existing gene variant in the population due to random chance, may cause gene variants to disappear completely or become more frequent
• Mechanisms of Evolution: Gene Flow


  Also called gene migration, introduces new alleles through interbreeding of migrating organisms from one population to another
• Evolution is a process of gradual change that takes place over many generations, during which species slowly change some of their physical characteristics
• Species


  Groups of interbreeding natural populations that are reproductively isolated from other such groups
• Reproductive Isolating Mechanism


  Collection of evolutionary mechanisms, behaviors, and physiological processes critical for speciation, preventing members of different species from producing offspring or ensuring sterile offspring
• Types of Isolating Mechanism

  • Pre-zygotic isolation mechanisms
  • Post-zygotic isolation mechanisms
• Pre-zygotic isolation mechanisms: Geographic or ecological or habitat isolation


  Occurs when two species that could interbreed do not because they live in different areas
• Pre-zygotic isolation mechanisms: Temporal or seasonal isolation


  Different groups may not be reproductively mature at the same time
• Pre-zygotic isolation mechanisms: Behavioral isolation

  Patterns of courtship differ, preventing interbreeding
• Pre-zygotic isolation mechanisms: Mechanical isolation

  Differences in reproductive organs prevent successful interbreeding
• Pre-zygotic isolation mechanisms: Gametic isolation

  Incompatibilities between egg and sperm prevent fertilization
• Post-zygotic isolation mechanisms: Hybrid inviability

  Fertilized egg fails to develop past the early embryonic stages
• Post-zygotic isolation mechanisms: Hybrid sterility

  Hybrids are sterile due to abnormal gonad development or chromosome segregation during meiosis