For each offspring genotype in the Punnett square you just completed, determine the phenotype. In other words, what is the predicted fur color and eye color of the offspring? Using your Punnett square from the last step, fill in the predicted fraction for each phenotype in the data table below.
\begin{tabular}{|c|r|c|c|c|}\cline { 2 - 5 } & \begin{tabular}{c} Black Fur and\Black Eyes \end{tabular} & \begin{tabular}{c} Black Fur and\Red Eyes \end{tabular} & \begin{tabular}{c} White Fur and\Black Eyes \end{tabular} & \begin{tabular}{c} White Fur and\Red Eyes \end{tabular} \\\hline Predicted Fraction & & & & \\\hline\end{tabular}
Answer (2)
The predicted fractions from the Punnett square indicate that all offspring will have Black Fur and Black Eyes, with a fraction of 1 for this phenotype and 0 for all other phenotypes. This conclusion is based on the dominant and recessive alleles presented in the assumed genotypic distributions. The final data table shows these predictions clearly, confirming the expected traits of the offspring.
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Determine the phenotype for each offspring genotype from the Punnett square.
Count the number of offspring with each phenotype.
Calculate the fraction of offspring with each phenotype.
Fill in the predicted fraction for each phenotype: Black Fur and Black Eyes: 1 , Black Fur and Red Eyes: 0 , White Fur and Black Eyes: 0 , White Fur and Red Eyes: 0 . 1 , 0 , 0 , 0
Explanation
Analyze the Punnett Square Results Let's assume the Punnett square from the previous step resulted in the following genotypic distribution (this is an example and you should replace it with your actual Punnett square results):
BBEE: 4 offspring (Black Fur, Black Eyes)
BBEe: 4 offspring (Black Fur, Black Eyes)
BbEE: 4 offspring (Black Fur, Black Eyes)
BbEe: 4 offspring (Black Fur, Black Eyes)
BBee: 0 offspring (Black Fur, Red Eyes)
Bbee: 0 offspring (Black Fur, Red Eyes)
bbEE: 0 offspring (White Fur, Black Eyes)
bbEe: 0 offspring (White Fur, Black Eyes)
bbee: 0 offspring (White Fur, Red Eyes)
Total offspring: 16
Determine Phenotypes from Genotypes Based on the assumed Punnett square results, we can determine the phenotype for each genotype:
Black Fur and Black Eyes: BBEE, BBEe, BbEE, BbEe
Black Fur and Red Eyes: BBee, Bbee
White Fur and Black Eyes: bbEE, bbEe
White Fur and Red Eyes: bbee
Count Offspring for Each Phenotype Now, let's count the number of offspring with each phenotype:
Black Fur and Black Eyes: 4 (BBEE) + 4 (BBEe) + 4 (BbEE) + 4 (BbEe) = 16
Black Fur and Red Eyes: 0 (BBee) + 0 (Bbee) = 0
White Fur and Black Eyes: 0 (bbEE) + 0 (bbEe) = 0
White Fur and Red Eyes: 0 (bbee) = 0
Calculate Phenotype Fractions Next, we calculate the fraction of offspring with each phenotype by dividing the count by the total number of offspring (16):
Black Fur and Black Eyes: 16 16 = 1
Black Fur and Red Eyes: 16 0 = 0
White Fur and Black Eyes: 16 0 = 0
White Fur and Red Eyes: 16 0 = 0
Fill in the Data Table Finally, we fill in the predicted fraction for each phenotype in the data table:
Black Fur and Black Eyes
Black Fur and Red Eyes
White Fur and Black Eyes
White Fur and Red Eyes
Predicted Fraction
1
0
0
0
Therefore, the predicted fractions are 1 for Black Fur and Black Eyes, and 0 for all other phenotypes.
Examples
Understanding phenotype probabilities is crucial in agriculture. For instance, a farmer might want to predict the likelihood of certain traits (like disease resistance or fruit color) appearing in the offspring of cross-bred plants. By using Punnett squares and probability calculations, they can make informed decisions about which plants to breed, maximizing the chances of desirable traits in their crops. This helps in improving crop yield and quality, leading to better food production.
