Cloning and Biotechnology

Cloning and Biotechnology

1. Natural cloning in plants

   • AKA vegetative propagation
     • It occurs in many species of flowering plants - it is where a totally new structure is forms which is genetically identical to the parent plant.
       • The new plant will either me (propagated) made from the stem, leaf bud or root. They will eventually be totally independent form the parent plant . EXAMPLES WOULD BE - Strawberry plants and spider plants.
       • This vegetative propagation involves perennating (to survive from one germinating season to another, especially under unfavourable conditions such as drought or winter) organ. These contain stored food from photosynthesis and can remain dormant in the soil.
         • THEY NOT ONLY A WAY OF ASEXUAL REPRODUCTION. They are a way of surviving from one season to the next
     • Cloning occurs in:
       • Bulbs
         • AN EXAMPLE:  Daffodil.  The leaf base swell with stored food from photosynthesis. The buds grow internally which develop into new shoots that will become new plants in the new season.
       • Runners
         • FOR EXAMPLE: strawberry plant or spider plant Runners are where there is a lateral stem growing away from the parent plant and the roots develop where the runner touches the ground. As the new plant develops eventually the runner withers away and leaves the new plant (clone) independent. 
       • Rhizomes
         • FOR EXAMPLE: Marram grass. They are specialized horizontal growing stems that grow underground. They are often swollen with a food storage. the new buds develop and form new vertical shoots that eventually become independent plants. 
       • Stem tubers
         • FOR EXAMPLE:  potatoes. The tip of an underground stem becomes swollen with stored food to form a tuber (or a storage organ). Buds on the tuber develop to produce new shoots (these are the eyes on potatoes) 
   • Farmers often use natural cloning to increase plant numbers cheaply (and to ensure that the new plants have the same genetic characteristics as the parent plant)
   • How to take cuttings of plants to ensure the offspring will be genetically identical and be good crop (if the parent is) : Take a short section of the stem amd plant in the ground or in a pot. Rooting hormone can be used at the base of the cutting to encourage the growth of new roots.
   • Cloning sugar cane (we clone sugar cane because its an important crop that is used to make sugar and manufacture biofuels) It is usually propagated by cloning. Short lengths of cane around 30cm long, with 3 nodes, are cut and buried in a clear field in shallow trenches and covered with a thin layer of soil.

2. Artificial cloning in plants

   • THIS PROCESS IS CALLED MICROPROPAGATION.
     • ADVANTAGES OF MICROPROPAGATION; Rapid priduction of crops, disease free plants (as its taken from the meristem), makes it possible to produce viable numbers of plants after the genetic modification of plant tissue, large production of seedless plants (for consumer), allows us to grow plants that are naturally reletively hard to grow from seed, provides a way of producing more of endangered species to save them from extinction.
     • DISADVANTAGES OF MICROPROPAGATION: produces a monoculture (so the plants are more suseptable to the same disease or a slight change in the growing conditions could kill them all), reletively expensive, must have skilled workers, explants and plantlets are suseptable to disease, in some cases there will be a loss of large numbers of new plants in the process
   • It is the process of making large number of genetically identical offspring from a single parent plant using TISSUE CULTURE techniques. They do this if the desired plant:
     • doesnt readily reproduce seeds, doesn't respond well to natural cloning, is really rare, has been genetically modified or selectively bred with great difficulty, is required to e pathogen free (like if its food produce)
   • Ways in which plants can be micropropigated:
     • Uses sterilising tablets - to help keep the plant tissues sterile without being in a steile lab so it is extremely helpful when woring with rare and endangered plant material.
     • Basics of micropropargation: Take a small sample of tissue from the plant that you want to clone (this tissue should be virus free, taken from the shoot tips and the axial to collect the meristem tissue and only be carried out in sterile conditions to ensure that there will be no contamination on fungi and bacteria). THEN, the sample is sterilised (usually be sterilising it in agents such as bleach, ethanol or sodium dichloroisocyanurate) The material that gets take from the plant is called the EXPLANT.. The explant that has been sterilised gets placed in a sterile culture medium which contains plant hormones (INCLUDING AUXINS + CYTOKINS which stimulate mitosis). the cells PROLIFERATE to form a mass of identical cells known as CALLUS. The callus gets divided up and individual cells or clumps of cells gets transferred to a new cuture medium that contains a different mixture of hormones and nutrients which will stimulate the growth of plantlets.
       • The plantlets can then be potted into compost where they will grow into small plants that can be then planted out to grow and reproduce a crop.

3. Cloning in animals

   • Natural cloning in ANIMALS? It is common in invertebrates and less common in vertebrates but still occurs in the form of twinning.
     • INVERTEBRATES - Starfish can completely regenerate entire animals from fragments of the original if they are damaged. Flatworms and sponges fragment and form new identical organisms in their natural reproductive process. HYDRA produce small buds on the sides of their body which eventually develop into clones. In some insects the females can produce offspring without mating (asexually)
     • VERTEBRATES - The main form of cloning is monozygotic twins. This is where the embryo splits to form two separates embryos - they look different due to the position with in the uterus and how much nutrition they are able to get.
   • Artificial cloning in ANIMALS
     • Artificial twinning
       • In cattle - Cow with desirable traits is treated with hormones so she SUPER OVULATES to produce more MATURE ova than usual. The avo then get fertilised (naturally or by artificial insemination) by a bull with good traits. The the early embryos get gently flushed out. Around day 6 (when the cells are still totipotent) the cells of the early embryo are split to produce several smaller embryos. It is then grown in the lab for a few days to make sure all is well and then it can be implanted into surrogate mothers (each embryo is implanted into different mothers so they will carry less risks) The embryos develop into foetuses and are born normally.
         • This technology allows us to increase the numbers of offspring produced by the animals with the best genetic stock - some of the eggs can be frozen and the succesfulness of the offspring can be assessed so if they did exeptionally well then they can implant the rest of the clones.
     • Somatic cell nuclear transfer
       • We are now able to clone adult animals by taking the nucleus from an adult somatic cell and transferring it to an enucleated egg cell ( an egg cell without a nucleus). Then a tiny electric shock is used to fuse the egg to the nucleus, stimulating the combined cell to divide and form a embryo that is a clone of the original adult.
         • The clones embryo can then be split to produce several identical clones.
     • Advantages of animal cloning
       • Artificial twinning enables high yielding of farming animals, enables success of the male animals passing on desirable genes to be determined if the first clone is successful then more can easily be implanted, SCNT enables GM embryos to be replicated + develop ehch increases the yield of animals coming from one engineering proceedure, SCNT enables us to be able to clone specific animals, SCNT enables us to reproduce rare, endanderges or event exhinct animals.
     • Disadvantages of animal cloning
       • SCNT is the biggest problem with the cloning of animals as it is a very inefficient process as it takes many eggs to produce a single cloned offspring, high proportion of animals miscarry or produce malformed offspring , offspring usually have shortened lifespans, SCNT has also been reletively unsuccessful with increasing the population of rare organisms or allowing extinct animals be brought back to life.

4. Microorganisms and biotechnology

5. Microorganisms, medicines and bioremediation

6. Culturing microorganisms in the labratory

7. Culturing microorganisms on an industrial scale

8. Using immobilised enzymes

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