Hardy-Weinberg Theorem explained by Aryan Doshi

Hardy-Weinberg Theorem is a mathematical expression that represents a population that is not evolving, or in genetic equilibrium. This means the allele frequencies or the variations of a trait will remain constant in this population. For example, if 70% of a fish population is red and the rest is pink, this will remain the same in 10 years, until the population evolves. The rules that must be followed are below.

1. No Gene Flow - no new members can enter or exit the population

2. No Mutations or Variations - variations introduce new alleles to a population and therefore allow for evolutions. 

3. Random Mating - Each allele needs to be passed on equally to the offspring. Therefore mating needs to be random and physical characteristics can not affect mating.

4. No Natural Selection - Natural Selection is when the environment chooses the individuals with the best adaptations to survive. This changes allele frequencies and causes evolution. 

5. Large Populations - A large population is required for a large sample size, which means small events do not heavily affect the population and allele frequencies. 

Furthermore, the Hardy-Weinberg Theorem also has math equations to go along with the rules. The equation p2+2pq+q2. Another equation is p + q = 1. The p in both equations represent the dominant allele. The q in both equations represents the recessive allele. These equations represent the percentages of the alleles. From the example before, the dominant allele is the redfish, and the recessive allele is pink. Alleles are represented by capital and lowercase letters. Each trait has one allele. So in this instance, p = 0.7, and q = 0.3, and the alleles will be C and c. In equation one, p2 will equal 0.49, and this represents the homozygous dominant allele or CC. 2pq will be 0.42, and this represents the heterozygous alleles or Cc. Both the p2 and the 2pq will show the dominant allele and be redfish. Q2 will represent the homozygous recessive trait and allele, of cc, with 0.09. To summarize, p = 0.7 and q = 0.3. Then, 0.49 represents the homozygous dominant, 0.42 represents the heterozygous, and 0.09 represents the homozygous recessive. 

 

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