p represents the frequency of the dominant allele (in decimal form) of a gene
q represents the frequency of the recessive allele (in decimal form) of a gene
These 2 alleles are different; one is dominant, one is recessive.
p^2 = the frequency of homozygous dominant individuals in the population (decimal form)
2pq = the frequency of heterozygous individuals in the population (decimal form)
q^2 = the frequency of homozygous recessive in the population (decimal form)
