Fig. 4.1 shows the relative frequency of the T allele in a population of 50 individuals over 20 generations. At generation 0, the numbers of T alleles and t alleles in the population were the same, so the relative frequency of each allele was 0.5. The relative frequencies of the two alleles in the gene sum to 1. Referring to Fig. 4.1, state the relative frequency of the t allele after 20 generations.
Suggest possible explanations for the change in the relative frequency of the T allele between generation 0 and generation 13.
The relative frequency of the T allele in a population of only 10 individuals was measured over 20 generations. The environmental conditions stayed unchanged throughout the experiment. Fig. 4.2 shows the results. Explain why Fig. 4.2 shows a different result from Fig. 4.1.
State the name of the principle that can be used to calculate relative frequencies of two alleles by counting the numbers of organisms in the population showing dominant and recessive phenotypes.