Population Genetics and Evolution

For today's class, we learnt about the Hardy-Weinberg law of genetic equilibrium and we studied the relationship between evolution and changes in allele frequency by using our 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 tast the chemical PTC could be estimated. If the person could tatse the bitterness, then the person is evidence of the presence of a dominant allele in eitherr the homozygous condition (AA)  or the heterzygous condition (Aa). If the person could not taste the chemical, then the person is evidence of the presence of homozygous recessive alleles (aa).

p= the frequency of the chemical tasting allele in the population

q= the frequency of the nontasting chemical allele 

phenotype= physical trait 

p^2 +2pq+q^2 = 1 (Population) 

p+q= 1 (frequency) 

p^2= AA

2pq= Aa

q^2= aa   

Hardy and Weinberg stated 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 are: 

1. The breeding population is 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.