Investigation II: Alleles in a Population

Investigation II: Alleles in a Population

Hypothesis: If the frequencies for the recessive allele and the dominant allele are both the same, then the number of organisms with homozygous dominant genes and homozygous recessive genes will be the same. 

Materials: Spreadsheet

Procedure:

1. Make a copy of the given spreadsheet.
2. Using the data from the spreadsheet, create a graph.
3. Label the independent variable (horizontal x-axis)
4. Label the dependent variable (vertical y-axis)
5. Title the graph

Graph 1:

This bar graph shows the alleles present in a population of 25 organisms.
A represents the dominant alleles while B represents the recessive alleles.

Graph Justification: 
In this first graph, you could see that the number of  dominant alleles, A, and the recessive allele, B, are the same. There are about 25 of each allele, A and B, because the frequencies of both alleles are 0.50.

Graph 2:

This bar graph shows the genotypes that are present in a population of 25 organisms.

Graph Justification: When the alleles were combined to form genotypes, the heterozygous genotype was found in a larger amount of organisms than the number of homozygous dominant and recessive genotypes. There were 11 heterozygous organisms compared to the 7 homozygous dominant and 7 homozygous recessive organisms. Both the homozygous recessive and dominant genotypes were equal because the alleles in these genotype had the same allele frequency.

Conclusion:
If all the homozygous genotypes, AA and BB, had an equal amount in a population, then my hypothesis would have been proven correct, but because the genotypes were randomly generated, my hypothesis won't always be correct.  There are times where amount of people with the homozygous dominant gene will appear greater than the amount of organisms with the homozygous recessive gene and vice versa.