Leq: what is cloning and how is it done?

1
Leq what is cloning and how is it done?

• 11.10 to 11.12

2
Cloning

• Cloning is the creation of a genetic copy of a
  sequence of DNA or of the entire genome of an
  organism
• There are three basic types of cloning
• Recombinant DNA technology the transfer and
  copying a segment of DNA from one organism to
  another
• Reproductive cloning generating an entire
  organism that is genetically identical to an
  existing organism
• Therapeutic cloning- the production of human
  embryos for the purpose of harvesting stem cells
  for research purposes

3
Dolly

• The 1st successful mammal clone created from a
  specialized body cell.
• Created at the Roslin Institute of Edinburgh
  University under the direction of Ian Wilmut
• There was concern that she would be born old
  because her DNA was from an adult sheep. Her
  telomeres were shorter than other sheep of her
  age but not as short as an old sheep. This
  could have played a role in her short life span
  (6 years normal 11 to 14 years)
• Before she died of cancer she was able to give
  birth to 6 lambs, the first of which was named
  Bonny

4
Reproductive Cloning

• Egg cell nucleus (haploid) is removed and
  replaced with a somatic cell nucleus (diploid)
• The egg cell is stimulated to induce cell
  division
• Once the dividing egg cell reaches the embryo
  stage it is implanted into a surrogate mother
• The embryo develops into a living organism

5
Benefits and Problems with Reproductive Cloning

• Benefits
• Genetic Research
• Restock populations of endangered animals
• Insure that good genes are passed to the next
  generation
• Problems
• Costly and inefficient (90 of the time it
  doesnt work)
• Short lifespan
• Susceptible to disease and illness results in
  early death

6
Ethical Issues with Reproductive Cloning

• Technical and medical safety
• Undermining the concept of reproduction and
  family
• Ambiguous relations of a cloned child with the
  progenitorConfusing personal identity and
  harming the psychological development of a
  cloneConcerns about eugenicsContrary to Human
  Dignity
• Promoting trends towards designer babies and
  human enhancement

7
Therapeutic Cloning

• Follow similar steps to reproductive cloning
  placing a somatic cell nucleus into an empty egg
  cell and stimulating cell division
• Big Difference the embryo is never implanted
  into a surrogate
• Instead, once the dividing egg reaches the
  blastocyst stage in development stem cells are
  harvested
• Embryonic stem cell lines are then established
  for research purposes

8
Benefits and Problems with Therapeutic Cloning

• Benefits
• The stem cells harvested can develop into any
  type of cell Can be used to develop treatments
  to diseases and possibly be used to create
  tissues/organs for transplant purposes without
  worrying about rejection by the immune system
• Problems
• Costly and inefficient requires that the embryo
  be destroyed so that stem cells can be harvested
  (is a blastocyst a living being?)