How could we keep track of the frequency of each allele for a given trait when we have a dominant-recessive interaction? More specifically, how could we account for the visible dominant traits as homozygous or heterozygous, since both look the same?

This is where the Hardy-Weinberg principle comes in. Firstly, there are criteria for when this principle may be applied to a population:

Random mating must take place.
No migration must occur either inwards or outwards of the population.
No mutations must arise in the population.
 No natural selection must take place due to one trait being better or worse adapted to the environment.

It’s apparent that this is simply rarely, if ever, the case in a real wild population. However, the Hardy-Weinberg principle is useful at predicting allele frequencies in a reliable mathematical…