22 - Cloning and Biotechnology Flashcards
Which type of reproduction is a type of cloning?
Asexual reproduction
What is cloning?
The production of offspring genetically identical to each other and to the parent
What is vegetative propagation also known as?
Natural cloning in plants
What happens in vegetative propagation?
A structure forms from a part of the parent plant which is genetically identical to the parent
What are 3 parts of a plant which vegetative propagation can occur from?
Leaves, roots, stem
What is vegetative propagation a means of except asexual reproduction?
Surviving from one growing season to the next
What do perennating organs enable a plant to do?
Survive adverse conditions
What are 4 examples of plant parts where natural cloning occurs?
- Rhizomes 2. Bulbs 3. Runners 4. Tubers
What is a rhizome?
A specialised underground stem which is often used as a food store
What is natural cloning used for in horticulture?
Producing new plants
What are 2 advantages of using natural cloning in horticulture?
- Increases plant numbers cheaply 2. Gives many genetically identical plants
What is often applied to cuttings to promote root growth?
Rooting powders
What can be taken from a plant for use in natural cloning?
Cuttings
What are 2 advantages of using cuttings instead of seeds to grow new plants?
- Much faster 2. Guarantees good quality of plants if the parent plant is of good stock
What is the main disadvantage of growing new plants using cuttings?
Lack of genetic variation in offspring can have negative impact if a new disease or pest appears
What are 4 plants commonly grown using cuttings?
- Bananas 2. Cassava 3. Sugar cane 4. Sweet potatoes
What is the most commonly used technique to artificially clone plants?
Micropropagation using tissue culture
What is micropropagation?
The process of making large numbers of genetically identical offspring from a single parent plant using tissue culture techniques
In what 5 situations would micropropagation be used to grow new plants?
“1. When the parent plant doesn’t readily produce seeds 2. When the plant doesn’t respond well to natural cloning 3. When the plant is very rare 4. When the plant has been genetically modified or selectively bred with difficulty 5. When the plant is required to be pathogen-free “
What can scientists in the field use to keep plant tissues sterile during micropropagation?
The sterilising tablets used to sterilise drinking water
What is used to sterilise plant tissue in industrial micropropagation?
Large sterilising units
What is the material removed from the plant in micropropagation called?
The explant
Why is a plant sterilised using water sterilisation tablets more likely to remain sterile?
The chemical doesn’t have to be washed off
What are 2 plant hormones found in the mixture used in micropropagation?
Auxins and cytokinins
What is a callus?
Mass of identical undifferentiated plant cells
Where does micropropagation now take place?
In bioreactors
What are the 6 steps of artificial plant cloning using tissue culture and micropropagation?
- Take small sample from parent plant 2. Sterilise it 3. Place it in sterile culture medium containing plant hormones until a callus forms 4. Divide it up and place in new mixture of hormones and nutrients until plantlets form 5. Pot plantlets until they grow into small plants 6. Plant out small plants to become a crop
What are 3 possible sterilising agents for use in artificial plant cloning?
- Bleach 2. Ethanol 3. Water sterilisation tablets
What are 6 arguments for micropropagation?
- Allows rapid production of good plants 2. Produces disease-free plants 3. Can produce viable amounts of plants after genetic modification of plant cells 4. Can increase numbers of rare plants 5. Can grow plants which are otherwise quite infertile and difficult to grow from seed 6. Can produce very large amounts of seedless, infertile plants to meet customer tastes
What are 5 arguments against micropropagation?
- Produces a monoculture, vulnerable to disease 2. Relatively expensive and needs skilled workers 3. Explants and plantlets vulnerable to infection by pathogens during production 4. If source material infected with virus, all new plants will also have virus 5. Sometimes large numbers of new plants are lost
What type of animals is natural cloning more common in?
Invertebrates
What is an example of how natural cloning can happen in animals?
Starfish can regrow an identical body from a small, detached fragment
What is the main form of vertebrate natural cloning?
Monozygotic (identical) twins
How are monzygotic twins formed?
The early embryo splits to form two identical embryos
Why may monozygotic twins still look different at birth?
Differences in positioning and nutrition in the uterus
Which animals can be relatively easily artificially cloned and how?
Some invertebrates, for example you can just chop off a bit of starfish to grow a new one
What are the 2 main methods of artificial cloning used in animals?
- Artificial twinning 2. Somatic cell nuclear transfer
What commercial sector uses artificial twinning?
Dairy and livestock farming
What is the principle of artificial twinning?
The early embryo is artificially split up to produce 2 or more genetically identical embryos
What do you have to do different when doing artificial twinning in pigs and why?
Implant a number of embryos into the mother pig as they usually have a litter of piglets, so an individual foetus may be rejected or reabsorbed by the mother’s body
What does artificial twinning enable you to increase?
The number of offspring which come from parents with the best genetic characteristics
Why might some embryos be frozen when doing artificial twinning?
You could implant a few unfrozen embryos and assess their success, and if they do well then you can unfreeze and implant the rest
What are the 5 stages of artificial twinning?
- Cow with desirable traits treated with hormones to make her superovulate 2. Fertilise the ova either naturally or via artificial insemination, then gently flush the early embryos from the uterus 3. While the cells are still totipotent, split the embryo into several smaller sections 4. Grow the embryos for a few days, then implant them into surrogate mothers 5. Embryos develop and are born normally
What is superovulation?
Hormonal treatment to increase number of ovulations
What can you do instead of fertilising the ova within a cow in artificial twinning?
Remove the mature eggs from the cow and inseminate them in the lab
Why, in cow artificial twinning, is one embryo implanted per mother?
Because single pregnancies are less risky than multiple pregnancies
What type of animal cloning is used to clone an adult animal?
Somatic cell nuclear transfer
Why are animals of different breeds used as the cell donor, egg donor and surrogate mother in Somatic Cell Nuclear Transfer?
To make it easier to identify the original animal at each stage
What type of cloning was used to produce Dolly the Sheep?
Somatic Cell Nuclear Transfer
What is Somatic Cell Nuclear Transfer also known as and why?
Reproductive cloning, as live animals are the end result
What are the 4 stages of Somatic Cell Nuclear Transfer?
- Nucleus removed from somatic cell of adult 2. Nucleus removed from mature ovum of different female of same species 3. Nucleus from adult animal placed in enucleated ovum and given mild electric shock to stimulate division 4. Embryo transferred to uterus of 3rd animal
What DNA of a clone produced by Somatic Cell Nuclear Transfer does not come from the original animal which had its nucleus taken?
Some mitochondrial DNA comes from the animal which provided the ovum
What are 2 ways in which Somatic Cell Nuclear Transfer is used currently?
- Pharming 2. Producing GM animals to grow organs for human transplant
What are 3 fields in which animal cloning is currently widely used?
- Agriculture 2. Animal breeding 3. Medicine
What are 5 arguments for animal cloning?
- Artificial twinning allows high-yield farm animals to have more offspring 2. SCNT allows specific good animals to be cloned 3. SCNT has potential to aid preservation of rare or even extinct animals 4. Artificial twinning allows the success of a male animal in passing on genes to be determined 5. SCNT enables GM embryos to be replicated and develop
What are 5 arguments against animal cloning?
- Scientists have been increasingly convinced that SCNT will not bring back extinct animals 2. SCNT is a very inefficient process 3. Many cloned animal embryos fail to develop properly and produce deformed offspring 4. Shortened lifespans for many animals 5. SCNT has been fairly unsuccessful so far in increasing the population of rare animals
What is biotechnology?
Applying biological organisms or enzymes to the synthesis, breakdown or transformation of materials in the service of people
What are 5 examples of biotechnology?
- Using yeast to make alcohol 2. Using yeast to make bread 3. Using fungi to make antibiotics 4. Using bacteria to clean up oil spills 5. Enzymes in biological washing powders
What are the 2 main types of organisms used in biotechnology?
- Bacteria 2. Fungi (Yeast)