Cloning and Biotechnology, 6.4 Flashcards
What is a clone?
A genetically identical organism
How can clones be produced in nature?
Asexual reproduction or twins
What are some advantages of Natural Clones?
- If conditions are good for the parents they will be good for the offspring
- Relatively rapid
- Can be carried with only one parent
What are some of the disadvantages of Natural Clones?
- Offspring become overcrowded
- No genetic diversity
- Population shows little variation
- Selection is not possible
- Entire population vulnerable to environmental changes
What is vegetative propagation?
Reproduction from vegetative parts of a plant - usually an overwintering organ
What is special about plant cells?
Many parts of the plant contain cells with the ability to divide and differentiate into a wide range of cells
What are runners, stolons, rhizomes and suckers?
- Plants grow horizontal stems that can form roots at certain points
- Underground thick growth at nodes, rhizomes
- Overground, runners and stolons
- New stems that grow from the root, suckers
What are bulbs?
- An underground stem which will grown into a new plant
- More than one apical bud
What are Tubers?
- Swollen part of an underground stem
- Can be cut into pieces which will grow into new plants
- Potatoes
What are Corms?
- Food store in stem tissue
- Solid, underground
- Can divide to produce more identical plants
What natural clones can be produced by animals?
Identical twins. Water flee and greenfly reproduce asexually
How are identical twins formed?
- Egg feritilised to form a zygote
- Zygote divides into two separate embryos
How can plants be cloned from cuttings?
- Stem cut between two leaf joints (nodes)
- The cut end is placed in soil
- New roots will grow from the stem
- Can produce large numbers quickly
- Usually dipped in rooting hormone
What is tissue culture?
Growing new tissues or organs from a sample plants tissue
What is micropropagation?
Growing a large number of new plants from meristem tissue taken from a sample plant
What are the stages of micropopagation?
- Plant material selected and cut into small pieces - called explants
- Explants sterilised in alcohol
- Placed on a sterile growth medium using suitable nutrients and growth hormones
- Cells divide and form a callus
- Callus divides to produced a larger number of small clumps of undifferentiated cells
- These clumps are stimulated to grow, divide and differentiate
- Tiny plantlets are formed and grown in a greenhouse
What are the advantages of micropropagation?
- Rapid production
- Carried out even if sexual reproduction is not possible
- Offspring will display desirable characteristics
- Uniform phenotype is easy to grow and harvest
What are the disadvantages of micropropagation?
- Labour intensive
- Expensive
- Can fail due to microbial contamination
- Will be susceptible to the same diseases
- No genetic variation
What are totipotent cells?
Cells that can divide and differentiate into all types eg embryo cells
What is reproductive cloning?
Produce large numbers of genetically identical animals through reproduction
What can reproductive cloning be used for?
Produce elite farm animals. Reproduce genetically modified animals with unusual characteristics
What is embryo twinning?
Splitting of an embryo. If an embryo splits early it can produced identical offpsring
What are the different stages of embryo twinning
- Zygote created by IVF
- Zygote is allowed to divide by mitosis to create a small ball of cells
- Cells are separated and allowed to continue dividing
- Each small mass of cells is placed into a surrogate
When is the phenotype of the clone know during embryo twinning?
After the animal is born
What is Somatic Cell Nuclear Transfer?
Transferring the nucleus of a somatic cell to an egg cell. Only way to clone an adult.
What are the stages of Somatic Cell Nuclear Transfer?
- Egg cell obtained and nucleus removed
- Somatic cell isolate, may have the nucleus removed
- Somatic cell or nucleus is fused with the egg cell by applying an electric shock
- Shock triggers the egg cell to start developing
- Undergoes mitosis to produce a small ball of cells
- Embryo is placed in a surrogate mother
When is the phenotype known during Somatic Cell Nuclear Transfer?
Before cloning
What is non reproductive cloning?
The production of cloned cells and tissues for uses other than reproduction
What are some examples of therapeutic cloning?
- Skin grow in vitro to act as a graft
- Cloned cells have been used to repair damage to spinal cord of a mouse
- Potential to grow new organs
What are the advantages of cloning animals?
- Produce large numbers of high value animals
- Can research the actions of genes and hormones
- Can test drugs
- Produce new organs, skin and other tissue
- Rare animals can be preserved
- Scientific testing, avoids using animals
What are the disadvantages of cloning animals?
- Lack of genetic diversity
- Animals produced with little regard for welfare
- Success rate is poor
- Long term affects unclear
- Ethical issues