PreLab Questions:1. Define the terms haploid and diploid.2. What information do we gain from doing a punnett square?3. Define the...

PreLab Questions:

1. Define the terms haploid and diploid.

2. What information do we gain from doing a punnett square?

3. Define the term allele.

4. How many copies of each trait are contained in a single gamete?

Click on the link below to access the online lab. http://www.mhhe.com/biosci/genbio/virtual_labs_2K8/pages/PunnettSquares.html Download and print the instructions for reference as you work through the lab. As you work through the lab fill in the table below. Use this information to answer the questions that follow contained in this document.

Complete all ten scenarios and record your results in Table 1. When you record a ratio, whether it is genotypic or phenotypic ratio, always record the most dominant characteristic first, followed by the recessive. Offspring Genotypes Genotypic Ratio Phenotypic Ratio* 1 GG, 2 Gg, and 1 gg 1 GG : 2 Gg : 1 gg 3:1 2 GG and 2 Gg 2

GG : 2 gg 1:1 4 gg 4 gg 0:4 * With monohybrid standard dominance traits there are only 2 possible phenotypes. The dominant and the recessive. You always report the dominant phenotype first followed by the recessive phenotype.

Table 1: Scenario # Genotype of Parent I Genotype of Parent II Genotypic Ratio of Offspring Phenotypic Ratio of Offspring 1 2 3 4 5 6 7 8 9 10

Post Lab Questions

5. If you mate two black flies what color(s) can their offspring be and why?

6. How can two flies with normal wings have offspring with vestigial wings?

7. Someone removed the labels from your fly jars. You have a jar of gray flies. Do you know their genotype? Why or why not?

8. You mate two gray normal winged flies and get offspring which are all gray but 25% of them have vestigial wings. What are the genotypes of the flies you mated? Explain your answer.

9. Explain how many phenotypes are there for a trait that has two alleles that are governed by incomplete dominance.

10. Explain how many phenotypes are there for a trait that has two alleles that are governed by co- dominance.