What is the Hardy-Weinberg Principle and how can I use the equation to help answer exam questions?

The Hardy-Weinberg principle is a mathematical model that predicts the frequencies of alleles in a population that won't change from one generation to the next. 

There are certain conditions that must be met by the population for Hardy-Weinberg to work 

e.g. There must be random mating amongst the population

e.g. There must be no immigration or emigration in and out of the population.

p2 + 2pq + q= 1

..where p= the frequency of the dominant allele

q= the frequency of the recessive allele

[p2 = frequency of homozygous dominant genotype]

[2pq = frequency of heterozygous genotype]

[q2 = frequency of homozygous recessive genotype]

Using this equation, you can input known values of frequency of alleles or of genotype to find the frequency of genotype of another category of the population. 

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