Knockout mice

• What can every biological process be traced back to?

  Genes
• How can specific diseases be linked to genes?

  Through mistakes in genes
• Why is understanding a gene's role in biology challenging?

  Because multicellular organisms are complex
• What important tool was developed over 30 years ago?

  The knockout mouse
• How can a knockout mouse be compared to baking a cake?

  Removing an ingredient affects the cake
• What does removing a single gene in an organism reveal?

  The key ingredient the gene provides
• What is the process of making a knockout mouse described as?

  Complex and took decades to develop
• What type of cells are isolated to create a knockout mouse?

  Embryonic stem cells
• What potential do most embryonic stem cells have?

  To develop into any cell or tissue
• What method is commonly used to remove a gene from ES cells?

  Homologous recombination
• What is used in homologous recombination?

  A piece of DNA with identical sequences
• What happens after the gene is removed from ES cells?

  They are inserted into a mouse embryo
• What are the resulting baby mice called after ES cells are inserted?

  Chimeric mice
• Why are they called chimeric mice?

  Named after the ancient Greek beast, chimera
• How is a complete knockout mouse generated?

  By breeding a partial knockout with a normal mouse
• What are heterozygotes?

  Mice with one copy of the target gene removed
• What is the goal of breeding heterozygotes together?

  To produce homozygous knockouts
• What prestigious award did the scientists involved in knockout mouse research win?

  Nobel Prize in Physiology or Medicine
• Why are knockout mice important for scientific advances?

  They provide insights into human biology
• What percentage of genes that make proteins are identical in humans and mice?

  85%
• What was one of the first examples of using knockout mice?

  Creation of a mouse model for cystic fibrosis
• How did knocking out the CFTR gene in mice help scientists?

  It recapitulated cystic fibrosis symptoms
• What diseases have mouse models advanced research for?

  Arthritis, cancers, and Parkinson's disease
• What recent technology has evolved knockout mouse technology?

  CRISPR-Cas9
• What is CRISPR-Cas9 based on?

  A naturally occurring immune system in bacteria
• What are the benefits of CRISPR-Cas9?

  It edits genes precisely and quickly
• How quickly can CRISPR-Cas9 create a knockout mouse?

  About six months
• What is a drawback of removing essential genes?

  It can lead to embryo death
• Why might removing a single gene not replicate all disease symptoms?

  Many diseases are impacted by multiple genes
• What is a limitation of observations made in mice?

  They may not translate to humans
• How have knockout mice contributed to biological laboratories?

  They are indispensable for scientific advances
• In what types of model organisms is knockout technology now used?

  Flies, worms, and fish
• What is the process of creating a knockout mouse?

  1. Isolate embryonic stem cells from a mouse embryo
  2. Use homologous recombination to remove a gene
  3. Insert modified ES cells into a mouse embryo
  4. Implant embryo into a female mouse
  5. Breed to produce homozygous knockouts
• What are the strengths and weaknesses of knockout mouse technology?

  Strengths:

  • Provides insights into gene function
  • Helps model human diseases
  • Allows for precise genetic editing

  
  

  Weaknesses:

  • Essential genes may cause embryo death
  • Single gene removal may not replicate diseases
  • Differences between mice and humans exist