Cloning and transgenic organisms – a virtual lab
BiologyBiotechnologyAges 15–16
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Sign in to playFour step-by-step procedures on a virtual bench. Split a cattle embryo into 2–4 parts and transfer them into surrogate cows; clone a sheep the way Dolly was made by somatic cell nuclear transfer (an udder-cell nucleus into an enucleated egg, electric shock, implantation into a surrogate) and predict which sheep the lamb resembles; clone plants by cuttings and by aseptic tissue culture; and make a GM organism with a restriction enzyme, plasmid, ligase, transformation and a marker gene, using insulin-making bacteria, Bt crops or Golden Rice. Every attempt goes into a results table, and benefit, risk and ethics cards are written neutrally.
Lesson: Cloning (embryo splitting, somatic cell nuclear transfer, cuttings, tissue culture) and genetically modified organisms
What it shows
Clones are genetically identical organisms. In embryo splitting, cells of an early embryo are separated before they specialise, and each part grows into an identical animal in a surrogate mother. In adult cell cloning, the nucleus of a body cell is put into an egg whose own nucleus was removed; an electric shock starts division, so the offspring carries the nucleus donor's genes, as Dolly did in 1996. Plants are cloned by cuttings or by tissue culture, which needs aseptic technique. In genetic modification, a gene is cut out with a restriction enzyme, joined into a vector with ligase and inserted into a host; marker genes identify the transformed cells.
How to use
Choose a tab, set the controls, then press the step buttons in order, or use Do the remaining steps; Skip this step leaves out optional steps. On 2. Nuclear transfer (Dolly), choose the face colour of sheep A, B and C and make a prediction before the lamb is born. On 3. Plant cloning, switch between Cuttings and Tissue culture. Each finished attempt adds a row to the Results table; press New attempt to repeat.
Parameters you can change
- Opening procedure Embryo splitting and transfer, Somatic cell nuclear transfer (Dolly), Cloning plants, Making a GM organism
- Number of parts the embryo is split into 2–4
- Sheep A, nucleus donor (udder cell) White face, Black face
- Sheep B, egg donor White face, Black face
- Sheep C, surrogate mother White face, Black face
- Reconstructed eggs per attempt 10–400
- Plant cloning method Cuttings, Tissue culture
- GM example Bacteria making human insulin, Insect-resistant Bt crop, Golden Rice (β-carotene)
- Marker gene Antibiotic resistance, Green fluorescent protein (GFP)
Questions to explore
- Why did Dolly have a white face like the udder-cell donor and not a black face like the egg donor?
- Why do many tissue-culture jars fail when the explants are not sterilised?
- Why is a marker gene needed when only a tiny fraction of cells take up the recombinant plasmid?
