Punnett Practice

Punnett Practice #1 T. Trimpe 2008 http://sciencespot.net/

1. Predict the offspring from a cross between a purebred tall pea plant and a hybrid tall plant. Use T for tall and t for short. (a) Give the genotypes. Purebred Tall = ____ Hybrid Tall = ____ (b) Create a Punnett square to determine the genotypes for the offspring. (c) What is the probability that a plant would be tall? _______ % (d) What is the probability that a plant would be short? _______ % 2. Predict the offspring from a cross between two hybrid tall pea plants. (a) Give the genotype for a hybrid tall plant. ______ (b) Create a Punnett square to determine the genotypes for the offspring. (c) What is the probability that a plant would be tall? _____ % (d) What is the probability that a plant would be short? _____ % (e) If you were to plant 100 seeds from this cross, how many would you expect to be tall?

T t T TT Tt T TT Tt 1. Predict the offspring from a cross between a purebred tall pea plant and a hybrid tall plant. Use T for tall and t for short. (a) Give the genotypes. Purebred Tall = ____ Hybrid Tall = ____ (b) Create a Punnett square to determine the genotypes for the offspring. (c) What is the probability that a plant would be tall? (d) What is the probability that a plant would be short? TT Tt 100% 0%

T t T TT Tt t Tt tt 2. Predict the offspring from a cross between two hybrid tall pea plants. (a) Give the genotype for a hybrid tall plant. ______ (b) Create a Punnett square to determine the genotypes for the offspring. (c) What is the probability that a plant would be tall? (d) What is the probability that a plant would be short? (e) If you were to plant 100 seeds from this cross, how many would you expect to be tall? Tt 75% 25% 25% of 100 = 25 plants

1. Predict the offspring from a cross between a purebred pea plant with purple flowers and a pea plant with white flowers. Use P for purple and p for white. (a) Give the genotypes. Purebred Purple = ____ White = ____ (b) Create a Punnett square to determine the genotypes for the offspring. (c) What is the probability that a plant would have purple flowers? _______ % (d) What is the probability that a plant would have white flowers? _______ % 2. If you crossed two hybrid plants with purple flowers and planted 200 of the seeds, how many would you expect to have with white flowers. Create a Punnett square to support your answer.

p p P Pp Pp P Pp Pp 1. Predict the offspring from a cross between a purebred pea plant with purple flowers and a pea plant with white flowers. Use P for purple and p for white. (a) Give the genotypes. Purebred Purple = ____ White = ____ (b) Create a Punnett square to determine the genotypes for the offspring. (c) What is the probability that a plant would have purple flowers? (d) What is the probability that a plant would have white flowers? PP pp 100% 0%

P p P PP Pp p You would expect to see white flowers on 25% of the plants, which would be 50 plants. Pp pp 2. If you crossed two hybrid plants with purple flowers and planted 200 of the seeds, how many would you expect to have with white flowers. Create a Punnett square to support your answer.

Some people have dimples, while others do not. The presence of dimples is a dominant trait (D), while not having dimples is recessive (d). (1) Susie has dimples, but her husband, Tom, does not. Their first child has his father's phenotype. What are the genotypes of the mother, father, and child? Mother’s Genotype: _______ Father’s Genotype: _______ Son’s Genotype: _______ (2) What is the probability that a second child won’t have dimples? Create a Punnett square to support your answer.

d d D d Dd Dd There would be a 50% probability that the second child would not have dimples. dd dd Some people have dimples, while others do not. The presence of dimples is a dominant trait (D), while not having dimples is recessive (d). (1) Susie has dimples, but her husband, Tom, does not. Their first child has his father's phenotype. What are the genotypes of the mother, father, and child? Mother’s Genotype: _______ Father’s Genotype: _______ Son’s Genotype: _______ (2) What is the probability that a second child won’t have dimples? Create a Punnett square to support your answer. Dd dd dd

In Dalmatians, the trait for black spots (B) is dominant over the recessive trait for no spots. Use this information to answer these questions. (1) Two Dalmatians with black spots have puppies. One of the dogs is homozygous for black spots, while the other is heterozygous. Out of a litter of 4 puppies, how many would you expect to have without spots? Create a Punnett square to support your answer. (2) Two Dalmatians had a large litter of 10 puppies. Seven of them have black spots, while 3 do not. What would the genotypes of the two parents need to be for this result? Create a Punnett square to support your answer.

B B B BB BB b Bb Bb (1) Two Dalmatians with black spots have puppies. One of the dogs is homozygous for black spots, while the other is heterozygous. Out of a litter of 4 puppies, how many would you expect to have without spots? Create a Punnett square to support your answer. None of them would be all white, since all the offspring would have black spots.

B B B B b b b B B Bb bb BB Bb b b b Bb bb Bb bb The parents would have both have to be Bb or heterozygous for black spots in order to have 7 out of 10 or about 75% of puppies with black spots. (2) Two Dalmatians had a large litter of 10 puppies. Seven of them have black spots, while 3 do not. What would the genotypes of the two parents need to be for this result? Create a Punnett square to support your answer. BB BB Bb Bb

1. One of SpongeBob’s cousins with hybrid round eyes (Rr) had children with someone who also had hybrid round eyes (Rr). A. Create a Punnett square to show the possible offspring that would result from this cross. B. Give the genotypes and phenotypes of the offspring. C. What percentage of the children should have round eyes? 2. Another of SpongeBob’s cousins with hybrid round eyes (Rr) had children with someone who has oval eyes (rr). A. Create a Punnett square to show the possible offspring that would result from this cross. B. Give the genotypes and phenotypes of the offspring. C. What percentage of the children should have round eyes?

R r R RR Rr r Rr rr 1. One of SpongeBob’s cousins with hybrid round eyes (Rr) had children with someone who also had hybrid round eyes (Rr). A. Create a Punnett square to show the possible offspring that would result from this cross. B. Give the genotypes and phenotypes of the offspring. C. What percentage of the children should have round eyes? RR = Round eyesRr = Round eyesrr = Oval eyes 75%

r r R Rr Rr r rr rr 2. One of SpongeBob’s cousins with hybrid round eyes (Rr) had children with someone who has oval eyes (rr). A. Create a Punnett square to show the possible offspring that would result from this cross. B. Give the genotypes and phenotypes of the offspring. C. What percentage of the children should have round eyes? Rr = Round eyesrr = Oval eyes 50%

Punnett Practice