# Hardy Weinberg Principle Video Tutorial

## Hardy Weinberg principle:

Hardy Weinberg principle, states that the frequencies of  genotype and allele will remain constant in a population from one generation to another generation if  there are no other evolutionary influences.

This video tutorial on Hardy Weinberg principle has been provided by: Khan Academy

Hardy Weinberg principle assumes:

1. No mutation occurring on the locus
2. No selection for any of the genotypes at the locus
3. Completely random mating
4. No migration

If a population is in the Hardy Weinberg equilibrium and p and q are separate alleles, then:

• Disease prevalence: p² + 2pq + q² = 1
• Allele prevalence: p+q = 1
• 2pq = heterozygote prevalence

Note:

• p = dominant allele
• q =  recessive allele
• pq = heterozygote allele

Hardy-Weinberg Principle

Let us solve an example in order to better understand how the Hardy Weinberg principle works. What is the frequency of BB phenotype and Bb phenotype if the frequency of allele B is 0.60 or 60% ?

First lets find out the allele prevalence by using the formula: p + q = 1

• The question already gave us “p” which is the dominant allele and it is 0.60, so now we can find out the allele prevalence by using this formula: p + q = 1
• Therefor: 0.60 + q = 1 (this is the same things as saying 60% + q = 100%)
• Now we have to solve for “q” —> q = 1 – 0.60
• Therefor: q = 0.4 or 40%

Now that we have both p (0.60) and q (0.40) we can plug them into our Hardy Weinberg principle equation (p² + 2pq + q² = 1):

• (0.60)² + 2(0.60 x 0.40) + (0.40)² = 1
• 0.36 + 0.48 + 0.16 = 1
• This is the same thing as saying, 36% + 48% + 16% = 100%

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