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.