The Hardy-Weinberg Principle helps us understand how genes change in a population. To use this principle, a few important rules need to be followed:

1. Big Population Size: The population should be large. This helps keep gene changes from happening by chance.

2. Random Mating: People in the population should pair up without any patterns. This way, all genes have an equal chance of being passed down to future generations.

3. No Mutations: There shouldn’t be any changes to the genes that add new versions. If mutations happen, it could change how often certain genes appear.

4. No Migration: No one new should come into the population, and no one should leave. This stops changes in gene mixes.

5. No Natural Selection: All genes should have the same chance to help survival. That means no particular trait is better than another.

When these rules are followed, we can use a special math formula to predict how often different genes will appear:

$p^2 + 2pq + q^2 = 1$

In this formula, $p$ and $q$ stand for how often two different genes show up in the population.