<p>Practice Mendelian Genetics</p><p>1. In tomatoes, red fruit is dominant to yellow fruit. A true breeding red-fruited plant is bred to a true- breeding yellow-fruited plant.</p><p> a. What are the phenotypes would you expect to see in the F1 offspring?</p><p> b. If two of the F1 plants were bred, what phenotypes would you expect to see in the F2 offspring?</p><p> c. What genotypes would you expect to see in the F2 offspring?</p><p>2. A brown mouse is mated to a white mouse and all of their offspring are brown.</p><p> a. Give symbols for the possible alleles. Which allele is dominant?</p><p> b. What are the genotypes of the mice that were mated?</p><p> c. If two of the F1 brown offspring are mated together, what percentage of the F2 mice will be brown?</p><p>3. A genetic cross between two F1-hybrid pea plants having yellow seeds will yield what percent green- seeded plants in the F2 generation? Yellow seeds are dominant to green.</p><p>4. In pea plants, tall is dominant over short. An F1 plant that is homozygous recessive is crossed with a heterozygous F1 plant. Use a punnett square to answer the following questions. </p><p> a. What percentage of the seeds from the cross will be homozygous dominant?</p><p> b. What percentage of the seeds from the cross will be heterozygous?</p><p> c. What percentage of the seeds from the cross will be homozygous recessive?</p><p> d. What percentage of the seeds from the cross will produce a tall plant?</p><p> e. What percentage of the seeds from the cross will produce a short plant?</p><p>5. A pure-breeding tall pea plant is crossed with a pure-breeding short pea plant. All of the offspring of this cross are tall. </p><p> a. Suppose two of the offspring of the F1 are crossed and produce 1000 offspring. How many tall and how many short will you expect? Answers </p><p>1. a. 100% red b. 75% red, 25% yellow c. 25% RR, 50% Rr, 25% rr</p><p>2. a. B = brown (dominant), B = white b. Bb x Bb c. 75% brown</p><p>3. Among the F2 plants of a Yy x Yy cross, 25% will be yy with the recessive, green-seeded phenotype</p><p>4. a. 0% b. 50% c. 50% d. 50% e. 50%</p><p>5. a. We would expect ¾ of the offspring to be either TT or Tt, so 750 tall; ¼ should be short, or 250.</p>