Hardy-Weinberg

In class, we learned about the Hardy-Weinberg law of genetic equilibrium and studied the relationship between evolution and changes in allele frequency by using our own class to represent a sample population. 

During this lab, we used the class as a population, the allele frequency of a gene controlling the ability to taste the chemical PTC could be estimated. If the person could taste the bitterness, then it is evident that the person has the presence of a dominant allele in either the homozygous condition (AA)  or the heterzygous condition (Aa). If the person could not taste the chemical, then the person has evidence of the presence of homozygous recessive alleles (aa).

p= the frequency of the dominant allele in the population

q= the frequency of the recessive allele 

p^2 +2pq+q^2 = 1 

p+q= 1 

p^2= AA

2pq= Aa

q^2= aa   

Hardy and Weinberg states that if 5 conditions are met, the population's allele and genotype frequencies will remain constant from generation to generation, meaning maintaining equilibrium. 

These conditions include: 

1. The breeding population has to be large. The effect of chance on changes in allele frequencies is thereby greatly reduced. 

2. Mating is random. Individuals show no mating preference for a particular phenotype. 

3. There is no mutation of the alleles. No alteration in the DNA sequence of alleles. 

4. No differential migration occurs. No immigration or emigration. 

5. There is no selection. All genotypes have an equal chance of surviving and reproducing.