Punnett Practice

1. Punnett Practice • A cross between 2 heterozygous plants yields 1252 offspring. How many are dominant and how many are recessive?

2. Answer • 313 recessive • 939 dominant

3. Punnett Practice #2 • A cross between a homozygous recessive parent and a heterozygous parent yields 350 dominant offspring. How many recessive would you expect? What is the total number of offspring?

4. Answer • 350 recessive • 700 total

5. Punnett Practice #3 • Two unknown parents cross and produce 36 offspring. 9 of them are homozygous dominant, 18 of them are heterozygous dominant, 9 of them are homozygous recessive. What is the genotype of the parents?

6. Answer • Both parents are heterozygous

7. Punnett Practice #4 • If a pea plant that is heterozygous for 2 traits (tall and purple) is crossed with a plant that is homozygous recessive (short and white), what portion of the 9,822 peas that are produced would yield plants that are tall and white?

8. Answer • Tall and white is T_pp • That’s 1/4 of 9822 • Which is 2,455.5 • or about 2456

9. Punnett Practice #5 • If a pea plant that is heterozygous for 2 traits (Tall and purple) is self pollinated, what portion of the 9822 offspring would be tall and white?

10. Answer • Tall and white is T_pp. • That’s 3/16 of 9822 • Which is 1,841.6 • or about 1842.