Genetic Engineering

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Principles of genetic engineering

L Mathias

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What is genetic engineering

Genetic engineering, also known as recombinant DNA technology, means altering the genes in a living organism to produce a Genetically Modified Organism (GMO) with a new genotype.

Various kinds of genetic modification are possible: inserting a foreign gene from one species into another, forming a transgenic organism; altering an existing gene so that its product is changed; or changing gene expression so that it is translated more often or not at all.

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Basic steps in genetic engineering

Isolate the gene

Insert it in a host using a vector

Produce as many copies of the host as possible

Separate and purify the product of the gene

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Step 1: Isolating the gene

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Step 1: Alternative method (using reverse transcriptase)

Reverse transcriptase

mRNA converted into cDNA

Complementary strand produced using DNA polymerase

Advantage – more mRNA in cell than DNA

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Step 2: Inserting gene into vector

Vector – molecule of DNA which is used to carry a foreign gene into a host cell

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Step 3: inserting vector into host

See worksheet

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Replica plating

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Step 4: Multiplication of the host cells by cloning

Large scale fermenters by cloning

All genetically identical because of asexual reproduction

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Step 5: Extraction of desired gene product