Gene Expression and Cloning Notes

Cloning and Gene Expression

• Cloning Development

  • Definition: The process through which a fertilized egg develops into a new organism.
  • Involves differentiation where cells specialize to perform specific functions via gene regulation.

• Stem Cells: Types

  • Embryonic Stem Cells:
  • Totipotent (can develop into any cell type).
  • Adult Stem Cells:
  • Pluripotent (can develop into several types of cells).
  • Example: Bone marrow stem cells.

• Cloning

  • Goal: To reverse differentiation ("de-differentiate" cells).
  • Types of Cloning:
  • Reproductive Cloning:
    • Creates a new individual genetically identical to another organism.
  • Therapeutic Cloning:
    • Produces stem cells for treatment that are genetically identical to an existing individual.

• Example: Cloning of Dolly the Sheep

  • Steps Involved:
  1. Nucleus Donation:
     • Differentiated adult cells are extracted from sheep A.
     • Cells are starved to stimulate de-differentiation.
  2. Egg Cell Preparation:
     • An egg cell is taken from sheep B, and its nucleus is removed.
  3. Nucleus Insertion:
     • The nucleus from sheep A is inserted into the egg cell from sheep B.
  4. Cell Division:
     • The fertilized egg begins to divide and forms an embryo.
  5. Implantation:
     • The embryo is implanted into the uterus of sheep C (the surrogate mother).
  6. Birth:
     • The embryo grows, and Dolly the sheep is born.

• Role of Activator Proteins / Transcription Factors

  • Present in the cytoplasm of the egg, these proteins are responsible for regulating gene expression during the early developmental stages.
  • Their activity is crucial for the successful cloning process and subsequent differentiation of cells.