Two-gene (dihybrid) crosses and 9

Question 1

Two pea plants, both RrYy (round, yellow seeds), are crossed. They produce 80 seeds. How many would you expect to be round and yellow (both dominant traits)?

Answer 

Question 2

Two guinea pigs, both Bb (black fur, B dominant), are crossed. What ratio of black to white offspring is expected?

• A. 1 : 1
• B. 1 : 1 : 1 : 1
• C. 3 : 1
• D. 9 : 3 : 3 : 1

Question 3

Assuming the genes are on different chromosomes, how many different kinds of gamete can an organism with genotype AaBbCcDd make?

Answer 

Question 4

Two pea plants, both RrYy (round, yellow seeds), are crossed. They produce 16 seeds. How many would you expect to be round and yellow (both dominant traits)?

Answer 

Question 5

Two guinea pigs, both Bb (black fur, B dominant), are crossed. What ratio of black to white offspring is expected?

• A. 9 : 3 : 3 : 1
• B. 1 : 1 : 1 : 1
• C. 3 : 1
• D. 1 : 1

Question 6

Assuming the genes are on different chromosomes, how many different kinds of gamete can an organism with genotype Aa make?

Answer 

Question 7

Two pea plants, both RrYy (round, yellow seeds), are crossed. They produce 48 seeds. How many would you expect to be wrinkled and green (both recessive traits)?

Answer 

Question 8

Two guinea pigs, both BbRr, are crossed. What ratio of phenotypes is expected in the offspring?

• A. 1 : 1 : 1 : 1
• B. 1 : 1
• C. 3 : 1
• D. 9 : 3 : 3 : 1

Question 9

Assuming the genes are on different chromosomes, how many different kinds of gamete can an organism with genotype Aa make?

Answer 

Question 10

Two pea plants, both RrYy (round, yellow seeds), are crossed. They produce 80 seeds. How many would you expect to be round and yellow (both dominant traits)?

Answer 

Question 11

Two guinea pigs, both BbRr, are crossed. What ratio of phenotypes is expected in the offspring?

• A. 3 : 1
• B. 9 : 3 : 3 : 1
• C. 1 : 1 : 1 : 1
• D. 1 : 1

Question 12

Assuming the genes are on different chromosomes, how many different kinds of gamete can an organism with genotype AaBbCcDd make?

Answer 

Question 13

Two pea plants, both RrYy (round, yellow seeds), are crossed. They produce 320 seeds. How many would you expect to be wrinkled and green (both recessive traits)?

Answer 

Question 14

A Bb guinea pig (black fur, B dominant) is crossed with a bb (white) guinea pig. What ratio of black to white offspring is expected?

• A. 9 : 3 : 3 : 1
• B. 1 : 1
• C. 3 : 1
• D. 1 : 1 : 1 : 1

Question 15

Assuming the genes are on different chromosomes, how many different kinds of gamete can an organism with genotype AaBbCc make?

Answer 

Question 16

Two pea plants, both RrYy (round, yellow seeds), are crossed. They produce 80 seeds. How many would you expect to be wrinkled and green (both recessive traits)?

Answer