Cloning in plants and animals

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• cloning is the production of genetically identical organisms/cells from an existing organsim  

1. Reproductive cloning

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   • used to make a complete organism that is genetically identical to another one
   1. uses

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      • use cloned animals for reserch purposes - variables that come from genetic difference are removed because they are all genetically identicalcan be used to save enndangered species from extinction by cloning animals can be used by farmers to increase the amount of animals with favourable characteristics that can be bred from or embryo split and placed in a number of organisms
      1. Exam q

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         • how cloning save endangered species increase rate of reproduction, not require species egg, not require female, female not at risk, succesfly formed embryo = subdiveded, use adult cells,
         • state 3 ways of setting up a gene bank for the darted buffalo sperm bank, tissue, zoo, emvyos as oocytes
   2. How?

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      • body cell (diploid) extracted from sheep a, normally taken from the udder/mammory gland nuclease extracteded and body cell discardered. nomally from high value organisms Sheep be has egg (hapolid) removed nuclease removed and discarder and egg cell kept nuclease from body cell is inserted into egg, fuse together (embryonic fusiion) using electrical impulses causing them to divide by mitosis embryo is then placed in utertus
      1. Exam q

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         • why does surrogate mother needed to be treated with hormones increase thicness of uterus lining, correct phase of cycle, sychronisation, prepare uterus for embryo
   3. exam q

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      • how are supply of egg cells obtained cow treated with hormones so she super ovulates and then washed out of oviduct and collected from ovaries
   4. Exam Q

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      • explaine why clone is no 100% genetically identical to pearent mitochondia dna in cytoplast fuse with buffalo cell. embryo has a mix of mito dna. has chromosomal dna from pearent  
2. Non reproductive cloning

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   • Sometimes called theraputic cloning, makes embryonic stem cells that are genetically identical to another organisms. NOT ORGANISM embryonic stem cells are harvested from younge embryos have the ability to become any cell type in an organism
   • stem cells are totipotend (able to form every different kind of cell) or pluripotent (able to form most of the different kinds of cell)
   1. uses

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      • could be used to replace damaged tissue in a range of diseases e.g. heart disease, spinal chord injuries, degenerative brain disorders like parkinsons tisue won't be rejected from immune system because it is genetically identical to organisms cloned fromused to investigate the involment of genes or external factors in development of diseases e.g cancer, diabetis or multipe sclerosiscan be used in gene therapy clone the cell that take up allele during somatic therapy which can then be placed in body stem cells could used to treat diseases where a group of cells have ceased to function - diabetisise and parkinsons
      • embryo at blastocyte stage are best source of stem cells could be used to make endless human cells but need to be indentical to organism they are used to treat
   2. Probelms

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      • hard to obtain as adults have minimal and only able to form into a few different cells
   3. How?

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      • body cell (diploid) extracted from sheep a, normally taken from the udder/mammory gland nuclease extracteded and body cell discardered. both from high value organism. Sheep be has egg (hapolid) removed nuclease removed and discarder and egg cell kept nuclease from body cell is inserted into egg, fuse together (embryonic fusiion) using electrical impulses causing them to divide by mitosis either placed in tied oviduct of sheep to produce embryo or in agarform an embryo 
3. Exam Q

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   • explain the meaning of the term clone organism genetically identical to pearent, produced via mitosis from one pearent, no gametes produces, produced by asexual reproduction.

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• Asexual reproduction in plants is often known as vegertative propgation (natural production of plant clones using from non reproductive tissue e,g, root leaves or stems) grown into identical new plant  

1. Elm Trees

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   • propgates itself by suckering, from the roots of pearent, grows from sucker bud, during times of stress sucker buds are activated only involves mitosis so new plant is genetically identical to pearent, all elm trees identical, no genetic variation, all derived fom one clone,
   • rare to find mature elm tree fungal disease spread by the elm bark beetle, reproduce by lying eggs in the bark dieing elm tree,the larvea hatch and burrow through the bark forming tunnels, fungus they are sapotrophic, forming spores, beetles grow and fly to new trees and carry fungal infection, fungus spores block the xylem so cannot co exist, all are suseptiable to the disearse, no variation on whiich natural selection can act, tree dies but roots still produce suckers, grown until fungus. Only option is mutation
   1. exam q x3

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      • Suggest a technique that could be used to provide molcular evidence that all english elms form a clone = genetic screening
      • state why the english elm are genetically isolated from other elms they reproduce a sexally, do not produce seeds, cross polinate
      • In 1967, a new, virulent strain of an elm disease fungus arrived in Great Britain on imported timber. Beetles that lived under the bark of elm trees spread the fungus. The saws used to cut down dead branches were not sterilised after use. When the saws were used to prune healthy trees, these trees became infected. Approximately 25 million elm trees, most of the English Elm population, died within a few years of the arrival of this fungus. Explain why there was such a rapid loss of elm trees in Britain as a result of this elm disease. genetically identical / little genetic variation ; 2 all susceptible / none resistant , to this disease ; 3 beetles , move / fly , from tree to tree or beetles are vector ; 4 trees grow , in clonal patch / close together or disease spreads through , suckers / roots or connected by , suckers / roots ; 5 the beetles only , live on / target , elm trees ; 6 attempts at control contributed to spread ; 7 as more trees became diseased then more tree surgery was necessary (contributing to spread of problem) ; 8 as more trees became infected then more , saws / equipment , were contaminated ;
2. other techniques

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   • tuber, runners, grafting, layering 
   1. Exam Q

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      • name one technique for producing clones of trees other than taking cuttings on micropropgation - grafting, budding, layering

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• produce cloones of particular desirable plant on a large scale all genetically identical produced from one or very few pearents 

1. 1. explant extracted

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   • small group of cells, normally from leaves as they are meristematic and can divide via mitosis
2. 2. sterilised

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   • tiny bundles of plant cells are very suseptible to fungal infection use disinfectant if contaminated all plants will be and will need to be disposed of 
3. 3.Aerated solution

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   • containg plant growth regulators in particular auxin and cytokinin = cell growth and division. solution also contains nutrients needed for cell growth = sucrose for energy and inorganic ions like nitrates magnesium and potassium  solution is sterile
   1. Exam Q

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      • list 3 consitiuates of the culture medium agar, aa, h20, sucrose, organic ions
4. advantages

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   • quick and cheap, any time of year, any country, any climate, small area, i grown in similar conditions will have flowers of same shape, colour and grow in particular parts of soil, guaranteed sales, 
5. Disadvantages

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   • labour intensive, risk of contaminaton, arrival of new pathogens and enviromental changes prove large threats, all are vunerable to same things, its important that many different plant varieties are kept all with their particular combo of allels = large gene pool from which new varities can be bred from in the future ,more labour intensive then annuels 
   1. Exam Q

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      • one disadvantage of micropropagation is the expense, list 3 factors that contribute to the cost sterile techniques, special equipment, trained staff, electric, quality control process, labour intensice
6. 4.Callus

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   • well a cell is damage cells close to the wound reproduce via mitosis = bundle of cells called a callus tissue culture stimulates cells to behave in this way
   • cells in aerated solution divide repeatdly via mitosis producing a callus the complete callus could be used or it could be subdivided 
7. 5. Sterile Agar

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   • grown on sterile agar with  particular mix of plant growth regulators that stimulate root and shoot growth, trial and erro has discovered balance of plant hormones in solution. one mix could be use to produce roots and another mix to produce shoots 
   1. Exam Q

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      • why is it impoartant for plants to develop root hairs
      • absorb water via osmosis, uptake IONS NOT MINERALS from soil e.g. nitartes through protein channels via active transport, preppare cutting for transplant to soil
8. 6. Hardening Medium

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   • when large enough moved to a more hardening medium like soil now exposed to fungal infections  this is a big risk 
9. Annuals

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   • propogation by seed and not cloning. seed sewn and crop harvested 6-10 months later  cheaper and easier than cloning 
   1. Exam Q

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      • state two advantages of using a clone instead of saplings grown from seeds
      • keep desirable characteristics, quciker, stronger, mass produce, disease free
10. Exam q

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    • micropropogation is one mehod used for the artificail propogation of new plants. Small amounts of tissue are obtained from plants and used to produce clones the info below is about the steps involved: tissue from apical bus is used, the surface of the tissue is cleaned using a sterilising agent, the growth medium contain cytokins, the growth medium contains magnesium ions, niutrate ions and sucrose, when shoots form they are transfered to a medium containing auxin
    • tissue ismeristematic are able to divide via mitosis, cleaned so is virus free, are unspecialised and undifferentiated, aspetic techniqus mainted as fungus and bacteria could compete, cytokines stimulate shoot growth, sucrose used for respiration, auxin stimulate root hair growth, magneisum for chlorophyll, nitrate for proteins and sucrose makes glucose for respiration

1. Advantages

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   • always have desirable characteristics - doesn't always happen with sexual reprodtuction, infertile animals can reproduce, animals can be cloned at any time
2. Disadvantages

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   • undesirable characteristics are always passed on to clones, difficult, time consuming, expensive, may not live very long
3. Ethichal Issues

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   • the use of human emvryos for the use of stem cells is controversial the embryos are destroyed after use some people believe doing this is destroying human life some people think a cloned human will have a lower quality of life undermines natural sexual reproduction & traditional family structure