• The sections of DNA that code for specific traits are called genes.

• DNA of all organisms contains the same 4 nucleotides (A, G, C, and T), but the arrangement of them varies.

• Therefore, different organisms inherit different genes.

• Info about DNA is useful in scientific studies, crime solving, agriculture, medicine, and more.

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​How is DNA useful to scientists?

• Chemical treatments cause cells and nuclei to burst.

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

• This is called "spooling" the DNA

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​DNA Extraction

• Technology that compares images of DNA fragments to determine relationships among individuals

• Restriction enzymes are used to cut a DNA molecule into smaller pieces

• They cut at specific sequences

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​DNA Fingerprinting

• The DNA fragments are then loaded into an agarose gel

• The gel is placed between positive and negative electrodes so that an electric current is passed through

• Objects with the same electrical charge repel each other

• DNA has a negative charge, so the fragments move away from the negative electrode and toward the positive electrode

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• Smaller fragments move more quickly and farther through the gel than larger fragments

• As the fragments become sorted by size, they appear as lines at different lengths along the gel

• The resulting pattern is called a DNA fingerprint

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DNA fingerprinting technology has several uses...

• The more similar the patterns in 2 DNA fingerprints, the closer the relationship of the organisms.

• Biologists can use the technique to identify related species and catalogue endangered species.

• It can also be used to identify a child's mother or father

• It can even be used as forensic data to solve crimes.