Name____________________



Name____________________ Date_______________pd____

Monohybrid Crosses WS #1

Genetic Problems

A. In cats, black fur (B) is dominant over white fur(b).

1. What is the symbol for the dominant trait?__________

2. What is the symbol for the recessive trait?__________

3. What are the two possible genotypes for a black cat?__________ and __________

4. What is the only genotype for a white cat?____________

B. A black female cat is mated with a white male cat. All four kittens are black.

5. What is the dominant trait?_______________

6. What is the symbol for the dominant trait?_________

7. What is the recessive trait?_______________

8. What is the symbol for the recessive trait?_________

9. What is the genotype of the white male?_____________

10. What gene did all the kittens inherit from the father?________

11. What gene did all the kittens inherit from the mother in order to be black?_________

12. What is the only genotype for the mother that would give all black kittens?_________

13. Is the mother cat homozygous or heterozygous?

14. Is the father cat homozygous or heterozygous?

15. Are the kittens homozygous or heterozygous?

16. What is the genotype of the kittens?

C. Another black female cat is mated to the white male. Four kittens result from this new feline fling. Two kittens are white, two kittens are black.

17. Work out the cross for these two parents. Use the cross to answer questions 18-29.

18. What is the dominant trait?________

19. What is the symbol for the dominant trait?_________

20. What is the recessive trait?________

21. What is the symbol of the recessive trait?_________

22. What is the genotype of the white male?__________

23. What gene do you know the black mother cat has?________

24. What gene did each kitten inherit from the father?________

25. What gene did the two black kittens inherit from the mother in order to be black?_______

26. What is the genotype of the black kittens?__________

27. What gene did the white kittens have to inherit from the mother to be white?__________

28. What is the genotype of the white kittens?_________

29. What is the mother cat’s full genotype?___________

D. In humans, the ability to taste the chemical phenylthiocarbonide is a dominant trait (T). People who cannot taste the chemical are called non-tasters and exhibit the recessive phenotype (t). Lola returns to Atlanta with her four-year old daughter, and is bringing child support charges against her old boyfriend Herman. Lola claims Herman is the father of the child. Herman claims that he is not the perpetrator and denies his fatherhood of the child. Lola is a non-taster, Herman is a non-taster, and the child is a taster.

30. What is the dominant trait?___________

31. What is the symbol for the dominant trait?___________

32. What is the recessive trait?____________

33. What is the symbol of the recessive trait?___________

34. What is Lola’s genotype?___________

35. What is Herman’s genotype?___________

36. Work out the cross between these two characters, and list the possible offspring they could produce.

37. According to the cross, what is the probability of the producing a non-taster child?______

38. What is the probability of the two producing a taster child?___________

39. Which person is lying about all the hanky-panky?__________________

E. In humans, brown eye color (B) is dominant to blue eye color (b). A brown eyed male marries a brown eyed female. They have a child that has blue eyes.

40. What is the symbol for brown eyes?______________

41. What is the symbol for blue eyes?_______________

42. What is the genotype of the child?______________

43. What gene do both parents have in order to produce

a child with blue eyes?__________

44. What gene do both parents have in order for them to have brown eyes?_____________

45. What is the complete genotype for both the mother and father?___________________

46. What would be the genotype of a brown eyed girl whose father had blue eyes?_________

F. Offspring of two parents are all heterozygous for brown eyes.

47. What is the genotype of one parent?_______________

48. What is the genotype of the other parent?___________

49. What is the genotypes of the children?___________

50. Fill out the cross to prove your answer.

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download