# Allele and Dd

1457 Words6 Pages
Name: Date: 03.05.13

Student Exploration: Hardy-Weinberg Equilibrium

Vocabulary: allele, genotype, Hardy-Weinberg equation, Hardy-Weinberg principle, heterozygous, homozygous, Punnett square

Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
Suppose the feather color of a bird is controlled by two alleles, D and d. The D allele results in dark feathers, while the d allele results in lighter feathers.

1. Suppose two Dd birds mate. What percentages of DD, Dd, and dd offspring would you predict? Use the Punnett square at right to help determine your answer.

DD ___25___ Dd _____50___ dd _____25_____

2. In this situation, what ratio of heterozygous (Dd) to homozygous (DD and
Interpret: Select the GENOTYPE GRAPH tab. What does this graph show? For Dd genotypes, it’s was the lowest but then it started going up. All of those results, Dd genotype have the highest average.

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Activity A (continued from previous page)

6. Gather data: On the DESCRIPTION tab, click Reset. Set DD and dd to any values you like. Fill in the initial values in the table below, and then run the Gizmo for five generations. Record the allele and genotype percentages for each generation in the table below.

| |Initial values |Generation |
| | |1 |2 |3 |4 |5 |
|% D alleles |74.0 |73.6 |74.3 |73.9 |75.5 |75.3 |
|% d alleles |26.0 |26.4 |25.7 |26.1 |24.5 |24.7 |
|% of DD genotype |68.0 |52.4 |55.6 |53.0 |58.0 |57.6 |
|% of Dd genotype |12.0 |42.4 |37.4 |41.8 |35.0 |35.4 |
|% of dd genotype |20.0 |5.2 |70. |5.2