Name:
Per:
Pedigree Practice
Use the pedigree to the left to answer the next 8 questions. Assume all fully shaded individuals have the
condition or trait.
1. What do circles and squares represent? ___________________
2. What do the shaded squares represent? _______________
3. What does a horizontal line between a circle and square
represent? _________________
4. What does a vertical line represent? ___________________
5. What does the half shaded circle represent? ___________
6. What does a square or circle with an “X” mean? ______________________________________________
7. Is this a dominant/recessive trait? _____________________
8. Based on the information given, is it possible that this trait is X-linked trait? ______ Why?
______________
Albinism
In humans, albinism is a recessive trait. The disorder causes a lack of pigment in the skin and hair making an albino
appear very pale with white hair and pale blue eyes. This disorder also occurs in animals. A common albino found in
a laboratory is a white rat. The pedigrees below trace the inheritance of the allele that causes albinism. Some circles
are squares are not correctly shaded.
9. Given the following genotypes, describe the phenotypes (normal or albino).
AA = ________________
Aa = ________________
aa = ________________
10. Examine the pedigree to the right. How many children
does this family have? ______________
11. What are the sexes of the children? ________________________
12. Fill in the genotypes on the lines next to the pedigree to the right
using AA, Aa or aa
13. Do you need to make any corrections to the pedigree, regarding what is fully shaded, half shaded or not shaded?
Make those corrections.
Another Albino Pedigree
14. Fill in the genotypes on the lines next to the pedigree below using AA, Aa or aa.
15. Do you need to make any corrections to the pedigree, regarding what is fully shaded, half shaded or not shaded?
The pedigree to the right that shows an undetermined trait. Use it
to answer the next 9 questions
16. How many generations are shown on the pedigree to the left? ______
17. Does any P generation person have sickle cell anemia? _____
18. How many children were born in the F1 generation? _____
19. How many children in the F1 generation are carriers for
sickle cell anemia? ________
20. How many children in the F2 generation have sickle
Below is part of the pedigree of Queen Victoria of England. This pedigree represents the
occurrence of hemophilia in her family. Only part of her family members has been
cell anemia? _________ How many are carriers? _________
included. Refer to this pedigree to answer the following questions:
21. Based on what you know, could sickle cell anemia be an X-linked trait? ______
22. How do you know? ___________________________________________
23. Is the gene for sickle cell anemia likely to be dominant or recessive? _____________
22. Explain your answer: __________________________________________________________________________
To the left is a partial pedigree of the English royal family. Assume that Queen Victoria’s daughter Alice, (top
level), is a member of the F1 generation. Hemophilia is an X linked trait.
24. How many male F1 individuals were hemophiliacs? __________
25. How many of the F2 grandchildren were hemophiliacs? ________
26. How many F3 were girls? _______
27. How many F3 were boys? _________
28. Is it more likely for males or females to get hemophilia? _________
29. Explain your answer. _______________________________________
30. Why were all the carriers in the royal family female? _________________________________________
Hemophilia is a sex-linked, recessive disease. Use the pedigree below to answer the next 3 questions
31. If spouses shaded in gray had a male child, what was the probability that he would be affected by the disease?
a. 0%
c. 25%
b. 50%
d. 100%
32. How many individuals in this pedigree have hemophilia?
a. 4
c. 2
b. 3
d. 1
33. Hemophilia is a result of blood not clotting properly. This condition is caused by a recessive allele carried on the
X chromosome. If a mother carries the hemophilia gene on one of her X chromosomes and she has children
with a man who exhibits hemophilia, which of the following may result?
a. all the daughters will have hemophilia
b. all the sons will carry hemophilia
c. all the daughters will carry or exhibit hemophilia
d all the sons will have hemophilia
This
Thisis is a pedigree showing a family with the allele for Huntington’s Disease
34. There are no carriers for Huntington’s Disease; you either have it or you don’t. With this in mind, is Huntington’s
disease caused by a dominant or recessive trait? _____________
35. Which members of the family above are afflicted with Huntington’s Disease? _________
36. How many children did individuals P-1 and P-2 have? ______________
37. How many total children of the F1 generation have the disease? ________________________
38. How are individuals F2-2 and F1-4 related? ________________________
39. How are P-2 and F2-5 related? _________________________
40. Does Huntington’s Disease appear to be sex linked? ______
41. How do you know? _____________________________________________________________
The pedigree to the right shows a family’s pedigree
for colorblindness. Females are rarely colorblind.
42. With this in mind, what kind of trait is
colorblindness? ______________________
43. Why do all the daughters in generation
F1 carry the colorblindness gene but do not
have the disorder?
___________________________________________
44.Why does individual F3-7 female have
colorblindness?
_________________________________________________
45. Name two F3 generation colorblind males. _________
**half-shaded = carrier of disease
This pedigree shows the inheritance of detached earlobes and attached earlobes in five generations of a
family. Attached earlobes are caused by a recessive allele (f).
46. Is individual 2 homozygous or heterozygous for free earlobes? __________
47. How do you know? _______________________________________________________________________
48. How many children of individuals 4 and 5 have attached earlobes? ________________
49. Can you be certain of the genotype of individual 5? _______
50. Explain. ________________________________ __________________________________
51. Predict the genotype and phenotype of individual 14. ______________________________
51. What is the name of the image below? ______________
52. Which chromosomes are autosomes? ______________
53. Does this picture show a normal number of human chromosomes? ____________
54. Explain. _______________________________________
55. Is this a male or female? _____________________