Cold Spring Harbor Laboratory
Dolan Dna Learning Center: Learn About Genetics: Genes & Inheritance
An animation introducing the basic concepts of cells, DNA, recessive inheritance, and Punnett squares.
PBS
Pbs Learning Media: Mendel's Laws of Genetic Inheritance
This interactive activity, adapted from the Dolan DNA Learning Center, uses Punnett squares to illustrate Mendel's laws of inheritance and how a particular gene combination results in a 3-to-1 ratio of dominant-to-recessive traits.