Cloning Flashcards
What is a clone?
An individual that is genetically identical to another/
What are the mechanisms of cloning?
Natural, embryo splitting, reprogramming somatic cells and nuclear transfer
How does cloning occur naturally?
By asexual reproduction, or if blastomere in two cell embryo splits naturally resulting in monozygotic twins
How does cloning occur by embryo splitting?
artificially splitting the embryo into two at early cell stages
How are somatic cells reprogrammed for cloning?
Differentiation may be reversible, e.g. in carrots, root cells can be tricked into forming a new plant that is a clone of the original one
What is Somatic cell nuclear transfer(SCNT)?
A lab technique for creating an viable embryo with an egg cell and a body cell, DNA from cell combined with fertilised egg that has been enucleated
Why is SCNT controversial?
Invasive and many technical problems. Also may be unethical
What two factors allow cloning by nuclear transfer?
Nucleus of every somatic cell contains a complete copy of individual genes and a fertilised egg is totipotent
Who cloned the first mammals?
Wilmut and Campbell in 1995, cloned sheep from cultured differentiated cells
When was dolly the sheep born and how did they achieve this?
In 1996, deprived adult sheep mammary gland cells of growth factor to arrest their development. These cells were fused with enucleated eggs, stimulated and transplanted to a surrogate
What are transgenic organisms?
Contains genetic material into which DNA from another unrelated organism has been inserted
Why did Wilmut and Campbell engineer a transgenic flock of sheep?
Goal was to create a flock that could produce therapeutically useful proteins, 7 lambs were born and 3 contained the transgender. One contained Human Factor IX, a cold clotting agent used for treating haemophilia
What are the potential uses of cloning?
Developmental research, using clones as controls Conservation Cloning of elite livestock Disease resistant farming Assisted reproductive techniques Therapeutic cloning
Why is it useful to pair cloning with genetic engineering?
Pharming
Xenotransplantation
What is xenotransplantation?
the process of grafting or transplanting organs or organ tissue between members of different species
What is Pharming?
Technology used to alter an animals own DNA
How is cloning used in conservation?
Can help threatened species, and has even brought a small number back from extinction
What are the problems with cloning for conservation?
How can you decide to clone one species over another, and it doesn’t address the reasons for species extinction in the first place
What is a common misconception cloning?
Doest bring back a loved one, they are only DNA clones, not cytoplasmic ones, have a mutations of their own, as well as being influenced form the environment
What are the problems with cloning?
Ageing - telomeres get shorter Large foetus syndrome Low success rate Lack of genetic variation In human cloning may be phycological problems
What happens to stem cells when given vitamin A derivatives?
Form nerve cells
How could they use stem cells to treat Parkinson’s disease?
dopamine producing cells in the brain die slowly in Parkinson’s patients, embryonic stem cells can be induced to produce dopamine in rates brain, next step is to develop system in humans
What are the moral/ethical problems with cloning?
Is it right to clone a human/animal?
is it right to clone for therapeutic purposes?
Issues surrounding the use of embryo cells
