Predicted vs. Observed Results

Problem: How do the predicted results compare to the actual results in a genetic cross as the sample size increases? Background: – Black is dominant fur color in mice, white is recessive. – What is the chance for getting a B or a b in a heterozygous mouse? Hypothesis:

Procedure: 1.Make a cross of Bb x Bb using a punnett square to find the expected results of crossing 2 heterozygous mice. 2.Mark 2 coins—B on one side and b on the other. Each coin represents one of the heterozygous mice. 3.Flip the coins together 40 times, and record the results of the offspring in table 1. 4.Calculate the percentage of the resulting phenotypes in table 1. 5.Repeat steps 1-4 except cross Bb x bb, changing one of the coins to b on one side and b on the other and use table 2 to record data.

Data: Gene combinations BBBbbb Total expected in 40 tosses Total observed in 40 tosses Phenotype Black White Total expected Total observed Table 1 BbxBb

Gene combinations BBBbbb Total expected in 40 tosses Total observed in 40 tosses Phenotype total # Black White Table 2 Bbxbb

spreadsheet

Data Analysis: 1.If I have a black mouse and I want to find out what its genotype is, how could I set up an experiment to determine the genotype of the mouse? 2.How did your expected results compare to your observed results? 3.How did the class expected results compare to the class observed results? 4.Explain what each side of the penny represented, what the flipping of the penny represented, how it relates to the chromosomes, and what the sides that were facing up represented.

Conclusion: Write a CER paragraph to explain how the predicted results compare to the expected results as the sample size increases.