1. Selective Breeding Limitations of selective breeding and mutations:
Selective breeding requires traits that already exist in a population – we cannot make new traits.
Mutations are unpredictable and will not create the exact traits that we want. (most mutations are harmful to the organism)
Scientists are learning how to directly manipulate the DNA of an organisms to produce desired traits.
Genetic Engineering: the development and application procedures, and technologies that allow you to directly manipulate an organisms DNA

2. Gel Electrophoresis
Gel Electrophoresis: Method for separation and analysis of macromolecules (DNA, RNA and proteins) and their fragments, based on their size and charge

3. Gel Electrophoresis Basic Steps for DNA Gel Electrophoresis
Mix a sample of DNA with a restriction enzyme.
Restriction Enzymes: a protein that cuts DNA at a specific nucleotide sequence.
Different samples of DNA produce fragments of different sizes.

4. Gel Electrophoresis 2. Separating the DNA fragments
A mixture of DNA fragments is put into one end of a porous gel
An electric current drives the DNA through the gel
The smaller the segment, the faster it moves.

5. Gel Electrophoresis 3. Analyzing the Results
Measure the distance the segment of DNA traveled away from the original position.
Smaller fragments of DNA move further across the gel.
DNA always has a negative charge, so it moves towards the positive electrode.