DNA Technology

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DNA Technology

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DNA Extraction

Chemical treatments cause cells and nuclei to burst

The DNA is inherently sticky, and can be pulled out of the mixture

This is called “spooling” DNA

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“Spooled” DNA

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Cutting DNA

Restriction enzymes cut DNA at specific sequences

Useful to divide DNA into manageable fragments

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Electrophoresis

DNA can be separated based on size and charge

The phosphate groups are negatively charged

DNA is placed in a gel and electricity is run through

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Electrophoresis

Negative DNA moves toward the positive end

Smaller fragments move farther and faster

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Electrophoresis

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Steps in DNA Sequencing

Many copies of a single strand of DNA are placed in a test tube

DNA polymerase is added

A mixture of nucleotides is added some of which have dye molecules attached

Each base (A,T,C,G) has a different color dye

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Steps in DNA Sequencing

By chance, some dyed nucleotides & some regular ones are added

Dye molecules are large and stop the chain from growing

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DNA Sequencing

The result is DNA fragments of multiple sizes with colors that can be identified

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DNA Sequencing

After the gel separates the resulting fragments by size, we 'read' the sequence from bottom to top.

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Copying DNA

Polymerase Chain Reaction

Also called PCR

A method of making many copies of a piece of DNA

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Steps in Copying DNA

A DNA molecule is placed in a small test tube

DNA polymerase that can work at high temps is added

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