Cloning

Noadswood Science, 2011

Cloning• To understand the process of cloning

Friday, April 21, 2023

Cloning – Plants• Cloning of plants has many important commercial implications – it

allows a successful variety of a plant to be produced commercially and cheaply on a massive scale in a short space of time

• Cloning is an example of asexual reproduction (where genetic information comes from just one parent)

• Cloning in plants can be via: -– Cuttings– Tissue cultures

Cuttings – Plant Cloning• Cuttings – the simplest way to clone a plant involves taking a cutting

• A branch from the parent plant is cut off, its lower leaves removed and the stem planted in damp compost – plant hormones are often used to encourage new roots to develop

• The cutting is usually covered in a clear plastic bag at this stage to keep it moist and warm

• After a few weeks, new roots develop and a new plant is produced – the method is easy enough for most gardeners to do successfully

Cuttings – Plant Cloning• Tissue culture – another way of cloning plants is by tissue culture, which

works not with cuttings but with tiny pieces from the parent plant

• Sterile agar jelly with plant hormones and lots of nutrients are needed, making tissue culture more expensive and difficult to do than taking cuttings

Tissue Culture – Plant Cloning1. Small amounts of parent tissue or a number of cells are taken

2. The plant material is transferred to plates containing sterile nutrient agar jelly

3. Plant hormones are added to stimulate the cells to divide

4. Cells grow rapidly into small masses of tissue

5. More growth hormones are added to stimulate the growth of roots and stems

6. The tiny plantlets are transferred into potting trays where they develop into plants

Tissue Culture – Plant Cloning1. Small amounts of parent tissue or a number of cells are taken

2. The plant material is transferred to plates containing sterile nutrient agar jelly

3. Plant hormones are added to stimulate the cells to divide

4. Cells grow rapidly into small masses of tissue

5. More growth hormones are added to stimulate the growth of roots and stems

6. The tiny plantlets are transferred into potting trays where they develop into plants

Cloning – Animals• People may want to clone an animal deliberately

• Just like the cloning of plants, the cloning of animals has many important commercial implications – it allows an individual animal with desirable features, such as a cow that produces a lot of milk, to be duplicated several times, however the process takes much longer than it does with plants

• Cloning in animals can be via: -– Embryo transplants– Fusion cell cloning

Embryo Transplants – Animal Cloning• A developing embryo is removed from a pregnant animal at an early

stage, before the embryo’s cells have had time to become specialised

• The cells are separated, grown for a while in a laboratory and then transplanted into host mothers

• When the offspring are born, they are identical to each other and genetically related to the original pregnant animal – they are not related to their host mothers because they contain different genetic information

Fusion Cell Cloning – Animal Cloning• Fusion cell cloning involves replacing the nucleus of an unfertilised egg with the nucleus

from a different cell – the replacement nucleus can come from an embryo, but if it comes from an adult cell, it is called adult cell cloning

• 'Dolly the sheep' was the first mammal to be cloned using adult cell cloning. She was born in the UK in 1996 and died in 2003: -

– An egg cell was removed from the ovary of an adult female sheep, and its nucleus removed

– The nucleus from an udder cell of a donor sheep was inserted into the empty egg cell

– The fused cell then began to develop normally, using genetic information from the donated DNA

– Before the dividing cells became specialised, the embryo was implanted into the uterus of a foster mother sheep which resulted in Dolly, genetically identical to the donor sheep

Fusion Cell Cloning – Animal Cloning

Cloning Experiment1. Open the sterile forceps and pick up a piece of the cauliflower. Put the

cauliflower and forceps into the beaker of bleach – wait 10 minutes

2. Pick up the cauliflower with the forceps again and quickly place it in a beaker of sterile water – wait 1 minute

3. Repeat the above step twice more with the two other beakers of sterile water

4. This step needs to be done quickly and carefully (decided what to do before your start) – take the tube of growth medium and place the cauliflower piece into the tube (have one person remove the foil, and another the cotton wool). The cotton wool and cover need to be replaced as quickly as possible

5. Leave the tube in a warm, light place (do not open the tubes again)

Fusion Cell Worksheet• Complete the fusion cell

worksheet

Fusion Cell Worksheet• Complete the fusion cell

worksheet