MYP Biology 9.2 Cloning Notes

What Is Cloning?

1. Cloning is the production of genetically identical cells or organisms.
2. This means the clone has the same DNA as the original despite bypassing sexual reproduction or the fusion of gametes.

How Does Natural Cloning Occur In Animals?

1. Identical twinning is a natural form of cloning:
   1. A single fertilised egg splits into two embryos.
   2. Each embryo develops independently.
   3. Both individuals have identical DNA.

How Does Natural Cloning Occur In Plants?

1. Many plants clone through vegetative propagation, where new plants grow from non-reproductive tissues.
2. Common methods include:
   1. Runners, such as in strawberries
   2. Tubers, such as in potatoes

How Can Cloning Be Done Artificially In Plants?

1. Cuttings
   1. A stem or leaf is removed from the parent plant.
   2. It is placed in soil or water to grow roots.
   3. A genetically identical plant develops.
2. Tissue culture
   1. A small tissue sample is taken from the plant.
   2. Cells are grown in nutrient-rich, sterile conditions.
   3. Many identical plants are produced.

How Can Animals Be Cloned Artificially?

1. One method involves splitting an early embryo:
   1. A zygote is first formed by sexual reproduction.
   2. The embryo begins early cell division.
   3. The embryo is split into two or more separate cell groups.
   4. Each group contains identical genetic material.
   5. Each embryo is implanted into a surrogate mother.
   6. Identical offspring develop.
2. A second method uses genetic material from an adult cell:
   1. The nucleus is removed from an adult body cell.
   2. The nucleus is removed from an egg cell.
   3. The adult nucleus is inserted into the enucleated (removed nucleus) egg cell.
   4. An electric shock stimulates cell division.
   5. The embryo develops and is implanted into a surrogate mother.

Who Is Dolly The Sheep Important?

1. Dolly was the first mammal cloned from an adult cell
   1. Cloned in 1996 using SCNT.
   2. Proved that adult cells still contain all genetic information.
2. Dolly raised scientific and ethical concerns
   1. Many failed embryos were produced.
   2. Dolly developed health problems and aged prematurely.

What Are The Risks And Challenges Of Cloning?

1. Animal welfare concerns
   1. High failure rates during development.
   2. Increased deformities and health issues.
2. Reduced genetic diversity: Populations become more vulnerable to disease.
3. Human cloning concerns: Identity, consent, and misuse of technology.
4. Low success rates: Many embryos fail to develop normally.
5. Developmental problems: DNA reprogramming may be incomplete.

What Are The Advantages And Disadvantages Of Cloning?