Genetic Engenering

7/24/2019 Genetic Engenering

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Kloning & RekayasaKloning & Rekayasa

GenetikaGenetika Kloning

DNA rekombinan

Kloning DNA

Aplikasi teknologiDNA rekombinandan DNA kloning

Bioteknologi Biotechnology refers to technology used

to manipulate DNA. The procedures areoften referred to asgenetic engineering.

DNA is the genetic material of all livingorganisms and all organisms use the samegenetic code. Genes from one kind oforganism can betranscribedandtranslatedwhen put intoanother kind of organism.

For example, human and other genes areroutinely put into bacteria in order tosynthesize products for medical treatmentand commercial use. Human insulin, humangrowth hormone, and vaccines areproduced by bacteria.

Recombinant DNA refers to DNA from twodifferent sources. Individuals that receivegenes from other species aretransgenic.


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Kloning

A clone is an organism which isgenetically identical to itsparent. Clones are the result ofasexual reproduction where onlyone parent is involved. The neworganism is formed by mitoticcell division

Clones frequently occur naturally.Potato plants reproducevegetatively by growing tubers

from which the new plant willgrow. Potatoes are clones.

Cloning in nature

A potato tuber is

geneticallyidentical to the

parent plant


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Other examples of cloning in nature are:

A colony of bacteria. Each bacterium splits intotwo, with the total number doubling everytwenty minutes - all genetically identical.

A clump of daffodils. The new plants arisingfrom the original bulb are exact replicas orclones of the parent (and of each other).

Strawberry or blackberry runners are clones of

the parent plant.

Artificial plant cloning

Cloning can also happen as a result ofhuman intervention. Tissue culture or

micro-propagation is a way of propagatingplants very quickly by taking a small number

of cells from a 'parent' plant and growingthem in a medium rich in nutrients and plant

growth hormones


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Plant cloning using tissue culture

This technique involves the following steps:

A small amount of parent tissue or a number of cellsare taken and

transferred to plates containing sterile nutrient agarjelly,

Auxins are added to stimulate the cells to divide bymitosis

Cells grow rapidly into small masses of tissue More growth hormones are added to stimulate the

growth of roots and stems The tiny plantlets are transferred into potting trays

where they develop into plants


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Animal cloning

Cloning also takes place naturally in thesimpler animals. Amoebas are single-celledprotozoa which reproduce by binaryfission, resulting in two offspring with identicalgenes

In more complex animals, cloning occurs whena fertilised egg splits to give identical twins.

Binary fission in the amoeba


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Artificialcloning of animals is now commonplace in laboratories.

The most famous example of animal cloning is Dolly the Sheep,born in the UK in 1996 using a technique called embryotransplanting.

Here's how it was done:1. An egg cell was removed from the ovary of an adult female

sheep, and the nucleus removed.2. Using micro-surgical techniques, the empty egg cell was

fused with DNA extracted from an udder cell of a donorsheep

3. The fused cell now began to develop normally, using thedonated DNA.

4. Before the dividing cells became specialised the embryo

was implanted into the uterus of a foster-mother sheep. Theresult was Dolly, genetically identical to the donor sheep.

Kloning pada

domba,

menghasilkan

domba Dolly pada

tahun 1996 di

Ingris


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Rekayasa Genetika Genetic engineering (also known as genetic

manipulationor GMis not the same ascloning. Though cloning techniques are usedin genetic engineering, the two things shouldnot be confused.

In the past, humans have brought aboutchange in the genetic make-up of organisms bymeans of selective breeding. Geneticengineering brings about such change byscientifically altering an organism's geneticcode

Perbedaan kloning & genetic enginering

Cloning Genetic engineering

Produces exact copies Produces a totally uniqueset of genes

Genes replicated withinthe same species

Genes can be swappedacross species


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In genetic engineering enzymes are used tocut up andjoin together parts of the DNA ofone organism, and insert them into the DNA ofanother organism.

In the resulting new organism the insertedgenes will code for one or more newcharacteristics - for example producing a newsubstance, or performing a new function. Theorganism has been genetically re-engineered

The diagram shows how a bacterium's genetic make-up can modified by

splicing a gene into its DNA. This technique is also known as gene splicing or recombinant DNAtechnology (because the DNA is recombined in the vector molecule).


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Teknologi DNA Rekombinan

Recombinant DNA is DNA that has beencreated artificially. DNA from two or more

sources is incorporated into a singlerecombinant molecule.

Vectors

Vectors are DNA used to transfer genesinto a host cell.

A vector must be capable of self-replicating inside a cell.

Marker genes can be used to determineif the gene has been taken up.

Marker genes must have somedistinguishable characteristic.

For example if you put a gene that

enables an ampicillin resistance on thesame vector as the same vector as thegene for human insulin production, thenany bacteria that grow on an ampicillinplate will be able to produce insulin.


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Plasmids

The host bacterium takes up the plasmid,which includes the foreign gene.

When the bacteria reproduces, theplasmids are also reproduced. The gene iscloned.

Shuttle vectors are plasmids that arecapable of existing in several different

species. They are useful when transferringgenes to multicellular organisms.

Viruses Viruses are the vectors of choice

for animal cells.

They can accept larger amounts ofDNA than plasmids.

When the virus reproduces withinthe animal cell, it also reproducesthe foreign gene that it carries.The gene is therefore cloned.

The DNA of some retroviruses

becomes integrated into the hostchromosome.


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Restriction enzymes

Restriction enzymes were discovered in bacteria.Bacteria use them as a defense mechanism tocut up the DNA of viruses or other bacteria.

Hundreds of different restriction enzymes havebeen isolated. Each one cuts DNA at a specificbase sequence. For example, EcoRI always cutsDNA at GAATTC as indicated below.

Enzyme Cutting Site

Bam HI GGATCC

Hae III GGCC

Pst I CTGCAG

Hinf I GANTC

Contoh enzim restriksi


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Sticky Ends

Fragments of DNA that has been cut withrestriction enzymes have unpairednucleotides at the ends called stickyends. All of the fragments will have thesame sticky ends.

The sticky ends have complimentarybases, so they could rejoin.

If the vector and the gene to be cloned are both cutwith the same restriction enzyme, they will both havecomplimentary sticky ends.


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Making Recombinant DNA

To make recombinant DNA, restrictionenzymes are used to cut DNA from two sourcessuch as the that of a vector and a gene to becloned. If the vector and the gene to be clonedare both cut with the same restriction enzyme,they will both have complimentary sticky ends(see above).

After cutting, the two samples of DNA are

mixed. Some of the fragments from one specieswill stick to those of the other because they bothhave the same sticky ends.

DNA ligaseis used to seal the fragments.

Bacteria are capable of taking up DNAfrom their environment.

This process is called transformation.CaCl2 and a procedure called heat shockare used to make E. colicells more

permeable so that they take up themodified plasmids more readily.


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Langkah dasar dalam kloning gen

Fragmen DNA yang diklon dimasukkan (insert)ke dalam DNA sirkular yang disebut vektoruntuk memproduksi chimaera atau molekulDNA rekombinan

Vektor berfungsi sebagai kendaraan akanmembawa gen ke dalam sel inang, biasanya

berupa bakteri yang mengandung plasmidatau bakteriophage

Di dalam sel induk, vektor akan mengalamipenggandaan sehingga menghasilkan banyakduplikat gen dari gen miliknya sendiri dan gen yangdimasukkan

Pada saat sel mengalami pembelahan maka seluruhgen yang ada pada sel akan diturunkan padaketurunannya

Setelah terbentuk koloni besar dari sel-sel inang yangmembawa vektor (pembawa gen asing yang biasa

disebut klon), masing-masing sel akan membawa satuatau lebih molekul DNA rekombinan. Gen yangdibawa oleh molekul rekombinan tersebut disebutklon DNA


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Kloning gen

DNA rekombinan

Sel yang mengandunggen yang diinginkan

bakteriIsolasi DNA plasmid danDNA yang mengandung

gen yang diinginkan

Gendiselipkan

dalam plasmid

Plasmid diletakkandi dalam sel bakteri

Bakteri rekombinan Sel diklon dengangen yang diinginkan

Identifikasi klonyang diharapkan

Berbagai aplikasi

Salinan gen diisolasidan ditrasfer ke

organisme lain Salinan produkprotein diisolasi

Gambaran umum bagaimana bioteknologi menggunakan plasmid bakteri untukmengklon gen


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Aplikasi Teknologi DNA

Kedokteran dan Farmasi Diagnosis penyakit

Terapi gen manusia

Produk farmasi

Forensik, Lingkungan dan Pertanian Forensik

Lingkungan

Pertanian Peternakan

Documents

Genetic Engenering