Analyzing Mendelian Genetic Experiments

Plant Height Experiment

1. Mendel studied how garden peas inherited plant height. He started with two true-breeding lines, one producing tall plants, the other short plants. We will use the capital letter "T" to represent the tall allele and a lowercase "t" for the short allele.
   1. We call these plants the parental generation, abbreviated as the   ___   generation.
   2. What is the genotype for the true-breeding tall plants ? _____
   3. Describe the phenotype for the tt plants. _______________________________
   4. Why are these plants called homozygous? ________________________________
2. Mendel crossed the two lines. He did this by placing pollen (male gametes) of a tall plant on the pistil (female part) of a short plant. Remember that a gamete will have ½ of the parent's genome. He saved the resulting seeds.
   1. What is the gamete allele of the true-breeding tall plants? ______
   2. What is the gamete allele of the true-breeding short plants? _______
3. Mendel grew the seeds of this first crossed generation. He found that the plants were all tall!
   1. The plants grown from the seeds are known as the   ____   generation.
   2. What is the genotype of the plants ? __________
   3. Which height trait is dominant? _______________
   4. Are these plants homozygous for height? ________
   5. The gametes of these F₁ plants have two possible alleles: ________     _______
4. Mendel then did nothing... these F₁ plants self-fertilized themselves. When Mendel planted the resulting F₂ seeds he found that 75% of the F₂ plants were tall and 25% were short.
   1. What are the three genotypes contained in the F₂ seeds? _____     _____     _____
   2. What is the genotype of the short plants ? _______
   3. What are the genotypes of the tall plants ? _______     _______     _______
   4. Which two genotypes would be true-breeding now ? _______     _____
   5. Which two genotypes would be homozygous ? _______     ______

Pod Color Experiment

1. Mendel also studied the pod color of garden peas. He started with two true-breeding lines, one producing green pods, the other yellow pods. We will use letter "G" to represent the green pod allele and a lowercase "g" for the yellow pod allele.
   1. We call these true-breeding plants the   ____   generation.
   2. What is the genotype for the true-breeding green pod plants ? ________
   3. Describe the phenotype for the gg plants. _______________________________
   4. Are these plants homozygous for pod color? _____________
   5. What is the gamete allele of the true-breeding green pod plant? _______
   6. What is the gamete allele of the true-breeding yellow pod plant? ________
2. Mendel crossed these two lines, saved the resulting F₁ seeds and grew them into F₁ plants.
   1. What is the genotype of the plants ? _________
   2. Describe the phenotype of the plants. ___________________________
   3. Are these plants homozygous for pod color? _________
   4. The gametes of the F₁ plants have two possible alleles: ______     _______
3. Mendel allowed the F₁ plants to self-fertilize. When he planted the resulting F₂ seeds they grew into a mix of green and yellow pod F₂ plants.
   1. What percentage of the plants had a GG genotype? ________
   2. What percentage of the plants had a Gg (or gG) genotype? ________
   3. What percentage of the plants had a gg genotype? _________
   4. Describe the phenotype for the Gg (or gG) plants. ____________________________
   5. Which two genotypes would be true-breeding now ? _______     ______
   6. Which genotypes would be heterozygous ? _______     ______

Using Punnett squares to analyze the plant height experiment

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Using Punnett squares to analyze the pod color experiment