Can you help me with the following questions:
Experiment 1: <?xml:namespace prefix = st1 ns = “urn:schemas-microsoft-com:office:smarttags” />Punnett SquareCrosses<?xml:namespace prefix = o ns = “urn:schemas-microsoft-com:office:office” />
In this experiment you will usemonohybrid and dihybrid crosses to predict patterns of inheritance.
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Part 1: Punnett Squares
- Set up and complete Punnett squares for each of the following crosses: (remember Y = yellow, and y = blue)
Y Y and Y y
Y Y and y y
- What are the resulting phenotypes?
- Are there any blue kernels? How can you tell?
- Set up and complete a Punnett squares for a cross of two of the F1 from Step 1 (above).
- What are the genotypes of the F2 generation?
- What are their phenotypes?
- Are there more or less blue kernels than in the F1 generation?
- Identify the four possible gametes produced by the following individuals:
Create a Punnett square using these gametes as P and determine the genotypes of the F1:
What are the phenotypes? What is theratio of those phenotypes?
Part 2 and 3 Setup
- Use the permanent marker to label the two 100 mL beakers as “1” and “2”.
- Pour 50 of the blue beads and 50 of the yellow beads into Beaker 1. Sift or stir the beads around to create a homogenous mixture.
- Pour 50 of the red beads and 50 of the green beads into Beaker 2. Sift or stir the beads around to create a homogenous mixture.
Assumptions for the remainder of theexperiment:
· Beaker 1 contains beads that are eitheryellow or blue.
· Beaker 2 contains beads that are eithergreen or red.
· Both beakers contain approximately thesame number of each colored bead.
· These colors correspond to thefollowing traits (remember that Y/y is for kernel color and S/s is forsmooth/wrinkled):
1. Yellow (Y) vs. Blue (y)
2. Green (G) vs. Red (g).
Part 2: Monohybrid Cross
- Randomly (without looking) take two beads out of Beaker 1. This is the genotype of Individual #1. Record the genotype in Table 1. Do not put these beads back into the beaker.
Table 1: Parent Genotypes: Monohybrid Crosses
Genotype of Individual 1
Genotype of Individual 2
- Repeat Step 1 for Individual #2. These two genotypes represent the parents (generation P) for the next generation.
- Set up a Punnett square and determine the genotypes and phenotypes for this cross. Record your data in Table 2
- Repeat Step 3 four more times (for a total of five subsequent generations). Return the beads to their respective beakers when finished.
Table 2: Generation Data Produced by Monohybrid Crosses
Possible Offspring Genotypes
Possible Offspring Phenotypes
Part 2: Monohybrid Cross
- How much genotypic variation do you find in the randomly picked parents of your crosses?
- How much in the offspring?
- How much phenotypic variation?
- Is the ratio of observed phenotypes the same as the ratio of predicted phenotypes? Why or why not?
- Pool all of the offspring from your five replicates. How much phenotypic variation do you find?
- What is the difference between genes and alleles?
- How might protein synthesis execute differently if a mutation occurs?
- Organisms heterozygous for a recessive trait are often called carriers of that trait. What does that mean?
- In peas, green pods (G) are dominant over yellow pods. If a homozygous dominant plant is crossed with a homozygous recessive plant, what will be the phenotype of the F1 generation? If two plants from the F1generation are crossed, what will the phenotype of their offspring be?