1. Sources of Variation
During Meiosis

2. Crossing Over
Process in which homologous chromosomes exchange portions of their chromatids during meiosis.

3. Random Assortment of Chromosomes
It is by chance that cells receive the chromosomes they receive during meiosis
Any chromosome could segregate to either cell

4. Gene Mutation
A random change in DNA can occur.

5. Nondisjunction
Error in meiosis in which homologous chromosomes fail to separate.
Can lead to genetic disorders.

6. Fertilization Joining of male and female sex cells
Random which cells (with different DNA) unite