Cloning
• outline the differences between reproductive and nonreproductive cloning;
• describe the production of natural clones in plants using
the example of vegetative propagation in elm trees;
• describe the production of artificial clones of plants from
tissue culture;
• discuss the advantages and disadvantages of plant cloning
in agriculture (HSW6a, 6b, 7c);
• describe how artificial clones of animals can be produced;
• discuss the advantages and disadvantages of cloning
animals (HSW4, 6a, 6b, 7c).
Outline the differences between reproductive
and non-reproductive cloning
Cloning = the production of genetically identical individuals
Reproductive Cloning = Using cloning to produce whole animals
Non-Reproductive Cloning = Using cloning to produce cells
Cells divide by binary fission, which means that they copy and split into two
Non reproductive cloning in humans was first done in 1951 from cancer cells from
a patient who died- this was done without the patient’s permission which would
be illegal nowadays
Now there are thousands of cells grown all over the world
They can be used to test potential drugs or can be used in DNA analysis to
investigate genetic diseases
Stem cells can now also be used which are non-differentiated (they are not
specialised) They are said to be totipotent (can form any type of cell) or
pluripotent (can form most types of cell)
There is some debate over stem cells as the best source are from embryos
Describe the production of natural clones in plants
using the example of vegetative propagation in elm
trees
Plants can clone themselves naturally by asexual reproduction, this is also
known as vegetative propagation
Barring mutation, vegetative propagation produces genetically identical
plants
Elm Trees: suckering occurs when trees are coppiced (chopped down a bit)roots form new shoots (called suckers or basal sprouts) that are genetically
identical and sprout up in a ring around the tree known as a clonal patch. As
they are identical they also suffer from the American Fungus that can kill the
‘parent plant’
describe the production of artificial clones of
plants from tissue culture
• Normally plants are cloned using their own natural method e.g.
strawberry plants making runners, potatoes from tubers etc.
• Gardeners and commercial growers use tissue cultures
Tissue Culture
1. Remove cells that are able to divide by mitosis (meristematic cells) from a
plant
2. This is now called an explant
3. This must be done aseptically so no contamination occurs
4. Immerse it in plant growth substances (auxin and cytokinin) also containing
sucrose, potassium, magnesium etc.
5. Undifferentiated cells divide to form a callus
6. Callus divided and placed on agar with growth substances
7. Plants then removed and planted
discuss the advantages and disadvantages of
plant cloning in agriculture
Advantages:
• All plants genetically identical
• Plants will mature at the same time and be
harvested at the same time
• Plants can be grown out of season
Disadvantages:
• Arrival of new pathogen or climate change will
affect all clones
• High costs involved
describe how artificial clones of animals can be
produced
• Nuclear transfer: skin cell taken, nucleus
removed, inserted into an empty egg cell,
transferred into a surrogate. The offspring is a
clone of the nucleus donor
• Splitting Embryos: fertilisation happens
normally, ball of cells split up and transplanted
into many surrogates. The offspring are clones
of each other but not of the parents
discuss the advantages and disadvantages of
cloning animals
Advantages
• Same genetic information
Disadvantages
• short life span