1. Punnett Square Practice
Genetics
Punnett Square Practice

2. For each problem List the genotypes of the parents.
Diagram and complete a Punnett square.
Give the phenotype percentages of the offspring.

3. #1
In garden peas, round seed coats (R) are dominant over wrinkled seed coats (r). What will the result be of a cross between a homozygous dominant male (____) and a recessive female (____)? RR rr

4. #1
In garden peas, round seed coats (R) are dominant over wrinkled seed coats (r). What will the result be of a cross between a homozygous dominant male (____) and a recessive female (____)? RR rr R r

5. #1
In garden peas, round seed coats (R) are dominant over wrinkled seed coats (r). What will the result be of a cross between a homozygous dominant male (____) and a recessive female (____)? RR rr R r Rr
Offspring: 100% Rr
100% heterozygous
100% round seed coats

6. #2
In peas, yellow color (Y) is dominant to green (y). What will the results be of a cross-pollination of a heterozygous male (____) and a heterozygous female (____)? Yy Yy

7. #2
In peas, yellow color (Y) is dominant to green (y). What will the results be of a cross-pollination of a heterozygous male (____) and a heterozygous female (____)? Yy Yy Y y

8. #2
In peas, yellow color (Y) is dominant to green (y). What will the results be of a cross-pollination of a heterozygous male (____) and a heterozygous female (____)? Yy Yy Y y YY Yy yy
Offspring:
25% YY; 50% Yy; 25% yy
25% homozygous dominant;
50% heterozygous;
25% recessive
75% yellow; 25% green

9. #3
In humans, straight toes (S) is dominant over curled toes (s). What would be the result of a cross between a recessive male (____) and a heterozygous female (____)? ss Ss

10. #3
In humans, straight toes (S) is dominant over curled toes (s). What would be the result of a cross between a recessive male (____) and a heterozygous female (____)? ss Ss s S

11. #3
In humans, straight toes (S) is dominant over curled toes (s). What would be the result of a cross between a recessive male (____) and a heterozygous female (____)? ss Ss s S Ss ss
Offspring: 50% Ss; 50% ss
50% heterozygous; % recessive
50% straight; 50% curled

12. #4
In dogs, erect ears (E) is dominant over droopy ears (e). What are the results if two heterozygous dogs (____) have a litter of puppies? Ee

13. #4
In dogs, erect ears (E) is dominant over droopy ears (e). What are the results if two heterozygous dogs (____) have a litter of puppies? Ee E e

14. #4
In dogs, erect ears (E) is dominant over droopy ears (e). What are the results if two heterozygous dogs (____) have a litter of puppies? Ee E e EE Ee ee
Offspring:
25% EE; 50% Ee; 25% ee
25% homozygous dominant;
50% heterozygous;
25% recessive
75% erect; 25% droopy

15. #5
In humans, eye color is due to more than one gene. If simply looking at one gene in particular, brown (B) eyes are dominant over blue (b). A brown-eyed man (____) marries a blue-eyed woman(____). They have three children, two of whom are brown- eyed and one of whom is blue-eyed. Bb bb

16. #5
In humans, eye color is due to more than one gene. If simply looking at one gene in particular, brown (B) eyes are dominant over blue (b). A brown-eyed man (____) marries a blue-eyed woman(____). They have three children, two of whom are brown- eyed and one of whom is blue-eyed. Bb bb B b

17. #5
In humans, eye color is due to more than one gene. If simply looking at one gene in particular, brown (B) eyes are dominant over blue (b). A brown-eyed man (____) marries a blue-eyed woman(____). They have three children, two of whom are brown- eyed and one of whom is blue-eyed. Bb bb B b Bb bb
Offspring:
50% Bb; 50% bb
50% heterozygous;
50% recessive
50% brown; 50% blue

18. #6
The ability to roll the tongue (R) is determined by a dominant gene while the recessive gene results in the inability to roll the tongue (r). A man and his wife can both roll their tongues and are surprised to find that their son cannot. Explain this by showing the genotypes of all three persons.
Note: You do not need to do a Punnett square for this problem.
Father:
Mother:
Son:
expresses dominant trait
RR or Rr
expresses dominant trait
RR or Rr rr
expresses recessive trait