Transcript cloning plants and animals

F215 control, genomes and environment
Module 2 – Biotechnology and gene
technologies
Learning Outcomes



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.
Cloning


Cloning is the production of
genetically identical organisms
In plants cloning can occur naturally
by asexual reproduction.
 All cells are produced by mitosis from cells
that were originally part of the parent
plant
 All plants are genetically identical to the
parent plant and each other.
Asexual reproduction

Advantages

Disadvantages
 Quick
 No genetic variety
 All offspring have the
 Does not allow for
genetic information
to enable them to
survive in the
environment
natural selection
 Unable to adapt to
environmental
conditions.
Vegetative propagation

Asexual reproduction in plants is
known as vegetative propagation
 Examples
▪ Strawberry plants produce runners
▪ Potatoes form underground tubers
▪ Daffodils produce bulbs
▪ English Elm produces root suckers (basal
sprouts)
Vegetative propagation in
potatoes
English Elm

The English Elm only
reproduces by
suckering
 The growth of new trees
from the roots or
meristem tissue in the
trunks

As all English Elms are
genetically identical
they are all susceptible
to the fungus, Dutch
elm disease
Artificial Vegetative
propagation

It is possible to artificially propagate
valuable plants
 Taking cuttings – cut a section of stem
between nodes, then treat with plant
hormones to encourage root growth
 Grafting – a shoot section of a woody
stem is joined to a root stock
 Tissue culture
Grafting
Tissue Culture


Tissue culture allows for the production
of huge numbers of genetically
identical plants from a small amount
of plant material.
All stages in tissue culture must be
carried out in sterile conditions to
prevent fungal infection
Stages in Plant Tissue Culture






A group of cells are removed from the
parent plant called the explant.
Explant is placed on a nutrient growth
medium
Cells divide to form a mass of
undifferentiated cells called a callus
Single cells removed from callus and placed
on a growth medium to stimulate shoot
growth
The shoots are placed on a growth medium
to stimulate root growth
Growing plants transferred to a greenhouse
before planting outside
Plant Cloning in Agriculture

Desirable parent plant can be chosen
and cloned
 Plants mature at same time

In UK, Annual crops are propagated
by seed
 After years of inbreeding all crops are now
genetically uniform
 Even though seeds require sexual
reproduction, all seeds and plants
produced are genetically uniform
Plant Cloning in Agriculture

In perennial plants, the high cost of
vegetative propagation is offset by
 the long periods for which the plants stay
in the ground
 Relatively high value of the product

Examples
 Lavender
 Apple trees
Disadvantages of plant cloning



Susceptible to disease
Unable to adapt to climate change
Loss of genetic variation
Learning Outcomes

Outline the differences between
reproductive and non-reproductive
cloning.
Cloning in Animals

Reproductive
cloning
 Cloning to produce
a whole organism
 Examples
▪ Embryo transplantation
▪ Dolly the sheep

Non-reproductive
cloning
 Using cloning to
produce cells
 Examples
▪ Stem cell research
▪ Production of cells,
tissues or organs
Non-reproductive cloning in
animals

Non-reproductive cloning involves the
production of genetically identical cells
 1951 – HeLa cells
▪ Cancerous cells which divide repeatedly in culture
solution
▪ Used in medical research
 Stem cells
▪ Totipotent or pluripotent
▪ Undifferentiated cells that are able to differentiate into
specialised cells
▪ Embryonic stem cells – ethical arguments
Possibilities of non-reproductive
cloning

Potential future uses include
 Regeneration of heart tissue following a
heart attack
 Repair of nervous tissue
 Repairing the spinal cord

Stem cells taken from the patient to
produce the tissues mean that tissue
rejection by the immune system is less
likely
Learning Outcomes


Describe how artificial clones of
animals can be produced.
Discuss the advantages and
disadvantages of cloning animals.
Reproductive cloning in
animals

Two methods of artificially cloning
animals
 Splitting embryos for embryo
transplantation
▪ All offspring are identical to each other but not
to the surrogate mothers
 Nuclear transfer using enucleated eggs
▪ Nucleus is taken from a differentiated cell in an
adult, and placed into a enucleated egg cell
Dolly the Sheep

Dolly the sheep is
believed to have
suffered from a
serious health
problem which
developed at a
relatively early age
Artificial Cloning in animals

Advantages

Disadvantages
 High value animals
 Animal welfare
 Rare animals can be
 Genetic uniformity,
cloned
 Quickly reproduced
loss of genetic
variation
 Uncertainties of
health of cloned
animals
Moral and ethical Arguments

Is it right to clone an aging pet?

Is it right to clone an animal which leads to a
cure for human diseases?