genome projects and genome technologies

• Genome Projects


  Projects that aim to sequence the entire genome of an organism
• Making DNA Fragments


  1. Gece cages an arcusy ang fromcing the esse run genose to chipping

  2. Sequencing Projects Have Read Entire Genomes

  3. Agore is fete set of DNA, ang all the genes in an openin

  4. 2 techealegy he allowed us to sequence fo

  5. wwws of a variety of ages for bacteria to haurs

  6. 4 The Hue Gene Project, which was completed in 2003,

  7. muggel the entire segance of the humus gesse for the first time
• Proteome


  All the proteins that are made by an organism
• Some parts of the genome code for specific proteins, while other parts don't code for anything at all (non-coding DNA)
• Simple organisms like bacteria have less non-coding DNA, making it relatively easy to determine their proteome from the DNA sequence
• Identifying protein antigens on disease-causing bacteria and viruses

  • Helps in the development of vaccines to prevent the disease
  • Example: Neisseria group B bacteria cause meningitis B, sequencing their genes helped researchers develop antigens for a vaccine
• Recombinant DNA technology


  Transferring fragments of DNA to produce a protein, even if the DNA doesn't come from the same organism
• Making DNA Fragments


  1. Using reverse transcriptase to make complementary DNA (cDNA) from mRNA

  2. Using restriction endonuclease enzymes to cut DNA at specific palindromic sequences
• Complex organisms contain large sections of non-coding DNA and complex regulatory genes, making it more difficult to translate their genome into their proteome
• Work is being done on the human proteome, with more than 30,000 human proteins identified so far
• Sequencing methods


  • In the past they were labour-intensive, expensive and small-scale
  • Now they are often automated, more cost-effective and can be done on a large scale
  • Example: Pyrosequencing can sequence around 400 million bases in a ten hour period
• Making DNA Fragments Using a 'Gene Machine'

  1. Design the required DNA sequence (if one doesn't already exist)

  2. Fix the first nucleotide in the sequence to a support (e.g. a bead)

  3. Add nucleotides step by step in the correct order, using protecting groups to prevent unwanted branching

  4. Produce short sections of DNA called oligonucleotides (roughly 20 nucleotides long)

  5. Break off the oligonucleotides from the support and remove the protecting groups

  6. Join the oligonucleotides together to make longer DNA fragments
• Amplifying DNA Fragments


  1. Insert the DNA fragment into a vector

  2. Transfer the vector with the recombinant DNA into host cells

  3. Identify transformed host cells using marker genes
• Vector


  Something used to transfer DNA into a cell, e.g. plasmids, circular DNA molecules in bacteria, or bacteriophages that infect bacteria
• Marker genes


  Genes inserted into vectors at the same time as the gene to be cloned, allowing identification of transformed host cells
• Promoter regions


  DNA sequences that tell the enzyme RNA polymerase when to start producing mRNA
• Terminator regions


  DNA sequences that tell RNA polymerase when to stop producing mRNA
• Without the right promoter and terminator regions, the DNA fragment won't be transcribed by the host cell and a protein won't be made
• In Vitro Amplification Uses the Polymerase Chain Reaction (PCR)


  1. Attach primers to DNA

  2. Heat DNA to 95°C to break bonds

  3. Cool to 50-55°C so primers can bind

  4. Heat to 72°C for DNA polymerase to work

  5. DNA polymerase adds free nucleotides to form new complementary strands

  6. Cycle repeats, doubling DNA each time
• Polymerase Chain Reaction (PCR)


  A technique used to make many copies of a DNA fragment
• PCR can be used to make many copies of a DNA fragment from a living organism
• Steps of PCR


  1. Attach primers to DNA

  2. Heat DNA to 95°C to break bonds

  3. Cool to 50-55°C so primers can bind

  4. Heat to 72°C for DNA polymerase to work

  5. DNA polymerase adds free nucleotides to form new complementary strands

  6. Cycle repeats, doubling DNA each time
• Each PCR cycle doubles the amount of DNA
• Transformed organisms are made using recombinant DNA technology
• Recombinant DNA technology


  • DNA segments from different sources are combined to create new genetic combinations
  • This allows the production of large quantities of specific proteins or other molecules
• Uses of transformed organisms

  • Agriculture - Crops with higher yields, pest resistance
  • Industry - Production of enzymes for industrial processes
  • Medicine - Production of drugs and vaccines
• Golden Rice is a variety of transformed rice that can produce beta-carotene, which the body uses to make vitamin A
• Insulin used to treat type 1 diabetes is now made from transformed microorganisms, using a human insulin gene
• Recombinant DNA technology


  The use of DNA technology to create new genetic combinations
• Concerns about the use of recombinant DNA technology

  • Ethical
  • Financial
  • Social
• Monocultures


  • Farmers planting only one type of genetically transformed crop
  • Whole crop vulnerable to the same disease
  • Reduces biodiversity
• Herbicide-resistant 'superweeds'


  • Can occur if genetically modified crops interbreed with wild plants
  • Uncontrolled spread of recombinant DNA with unknown consequences
• Organic farmers' crops


  Can be contaminated by wind-blown seeds from genetically modified crops
• Globalisation and biotechnology companies


  • Anti-globalisation activists oppose growth of large multinational companies at the expense of smaller ones
  • A few large biotechnology companies control some forms of genetic engineering
• Lack of proper labelling


  People may not have a choice about consuming food made using genetically engineered organisms
• Some consumer markets


  Won't import GM foods and products, causing economic loss to producers
• Ownership issues with recombinant DNA technology


  • Debate about who owns genetic material from humans once removed from the body
  • A small number of large corporations own patents to particular seeds and can charge high prices
• Potential humanitarian benefits of recombinant DNA technology

  • Producing agricultural crops to reduce famine and malnutrition
  • Producing useful pharmaceutical products like vaccines
  • Producing medicines more cheaply
• Gene therapy


  Altering defective genes inside cells to treat genetic disorders and cancer
• How gene therapy works

  1. Altering defective genes (mutated alleles) inside cells

  2. Inserting a working dominant allele to make up for mutated recessive alleles

  3. Silencing a mutated dominant allele