Biology: The Ultimate Pedigrees Quiz!

28 Questions | Total Attempts: 4729

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Biology: The Ultimate Pedigrees Quiz!

Do you want to test your genetic knowledge? This quiz is based on a pedigree diagram that represents biological relationships between an organism and its ancestors. Let's play this quiz and prove yourself!


Questions and Answers
  • 1. 
    • A. 

      1 in 4 for a son, close to zero for a daughter

    • B. 

      1 in 2 both for sons and daughters

    • C. 

      1 in 2 for a son and 1 in 4 for a daughter

    • D. 

      1 in 2 for a son, close to zero for a daughter

    • E. 

      1 in 4 both for sons and daughters

  • 2. 
    • A. 

      100% for a son and 50% for a daughter

    • B. 

      100% for a son, zero for a daughter

    • C. 

      50% for a son, zero for a daughter

    • D. 

      50% for both sons and daughters

    • E. 

      25% for a son and zero for a daughter

  • 3. 
    II-3 in the below family has two brothers with hemophilia and three healthy sons. How likely is it that she is a carrier of the hemophilia gene?
    • A. 

      1 in 4

    • B. 

      1 in 2

    • C. 

      1 in 16

    • D. 

      1 in 3

    • E. 

      1 in 9 (Bayes’ Formula)

  • 4. 
    • A. 

      X linked recessive; 1 in 2 for a son and 1 in 4 for a daughter

    • B. 

      Autosomal recessive; 1 in 2

    • C. 

      Autosomal dominant; 1 in 2

    • D. 

      Autosomal recessive; 1 in 4

    • E. 

      Mitochondrial; 1 in 2

  • 5. 
    • A. 

      75%

    • B. 

      50%

    • C. 

      25%

    • D. 

      100%

    • E. 

      Virtually zero

  • 6. 
    In the family below, two brothers have classical hemophilia. Now I-4 asks you about the risk that her children will have hemophilia. You can tell her that the risk is:
    • A. 

      Close to zero for both sons and daughters

    • B. 

      1 in 2 for a son, close to zero for a daughter

    • C. 

      1 in 4 for both sons and daughters

    • D. 

      1 in 4 for a son, close to zero for a daughter

    • E. 

      1 in 8 for a son, close to zero for a daughter

  • 7. 
    • A. 

      1 in 4 for both sons and daughters

    • B. 

      1 in 4 for a son, close to zero for a daughter

    • C. 

      1 in 2 for a son, close to zero for a daughter

    • D. 

      1 in 8 for a son, close to zero for a daughter

    • E. 

      1 in 2 for both sons and daughters

  • 8. 
    Now assume that I-4 (above) has two healthy sons. In that case, you can use Bayes' theorem to figure out that her chance of being a carrier is:
    • A. 

      10%

    • B. 

      20%

    • C. 

      50%

    • D. 

      12.5%

    • E. 

      33%

  • 9. 
    • A. 

      1 in 4

    • B. 

      1 in 200

    • C. 

      1 in 50

    • D. 

      1 in 100

    • E. 

      1 in 25

  • 10. 
    Now assume that the unaffected sister of an albino asks you how likely it is that her child with a healthy unrelated man will be an albino. Her parents are both unaffected. Assume again a carrier frequency of 2% in the general population.
    • A. 

      1 in 800

    • B. 

      1 in 75

    • C. 

      1 in 300

    • D. 

      1 in 50

    • E. 

      1 in 150

  • 11. 
    The pedigree below represents a family with cystic fibrosis (autosomal recessive). What is the risk that individual II‑2 will have an affected child if the prevalence of cystic fibrosis is 1 in 2500 individuals?
    • A. 

      1/100

    • B. 

      1/150

    • C. 

      1/25

    • D. 

      1/50

  • 12. 
    A woman (I‑1) is deaf from an autosomal recessive disease. She marries a hearing man and has four children, two of the four children are deaf at an early age. Genomic DNA was isolated from peripheral blood lymphocytes from all family members and subjected to Southern blot analysis using a radiolabeled DNA probe known to be strictly linked to the disease gene. Which of the following statements is TRUE about the offspring in generation II?
    • A. 

      II 1 will be a carrier and II 3 will be normal

    • B. 

      II 1 will be normal and II 3 will be a carrier

    • C. 

      Both II 1 and II 3 will be carriers

    • D. 

      Both II 1 and II 3 will be normal

    • E. 

      II 1 will be affected and II 3 will be normal

  • 13. 
    A 4‑year‑old boy was brought to the emergency room by his mother after falling three steps. The boy had skinned his knee and forearm on the cement and showed unusual and extensive bruising. To determine the genotype of the family members, genomic DNA was isolated from peripheral blood lymphocytes and subjected to Southern blot analysis using a radiolabeled DNA probe known to be closely linked to the disease gene. The boy is indicated by the arrow. Which of the following statements is TRUE about his siblings in generation III?
    • A. 

      III -1 will be a carrier and III - 2 will be normal

    • B. 

      Both III -1 and III- 2 will be affected

    • C. 

      Both III- 1 and III -2 will be normal

    • D. 

      III -1 will be affected and III -2 will be a carrier

    • E. 

      Both III -1 and III -2 will be carriers

  • 14. 
    Genomic DNA was isolated from peripheral blood lymphocytes from the indicated family members subjected to Southern blot analysis using a radiolabeled DNA probe known to be strictly linked to the disease gene. The clinical manifestations of the autosomal dominant form of Martin's syndrome have been identified in this family, as indicated by the filled symbols. Given that the population frequency of Marfan's syndrome is 1 in 10,000, which of the following statements is TRUE about the siblings in generation III?
    • A. 

      III -1 will not be affected and III -3 will be affected

    • B. 

      Both III - 1 and III- 3 will be affected

    • C. 

      III -1 and III -3 will NOT be affected

    • D. 

      III -1 will be affected and III -3 will not be affected

    • E. 

      It can not be determined whether III 1 and III 3 will be affected based on the data presented

  • 15. 
    • A. 

      This is an x- linked recessive disease, the mutant allele was received from the mother (II- 2), and she will be a carrier

    • B. 

      This is an x linked recessive disease, the mutant allele was received from the father (II- 1), and she will see a carrier

    • C. 

      This is an autosomal dominant disease, the mutant allele was received from the mother (II- 2), and she will be affected

    • D. 

      This is an autosomal dominant disease, the mutant allele was received from the father (II- 1), and she will be affected

    • E. 

      This is an autosomal dominant disease, the mutant allele was not inherited from either the mother or father, and she will not be affected

  • 16. 
    Your father has a dominantly‑inherited form of retinitis pigmentosa, an eye disease that leads to blindness in middle‑aged people. Now you are 25 years old, and you took a vision test to check whether you are developing this disease. In two-thirds of all people your age who carry the gene, the vision test is abnormal while in one third it is still normal. Your analysis was normal. How LIKELY is it that you carry the gene? Use Bayes' theorem.
    • A. 

      1 in 2

    • B. 

      2 in 3

    • C. 

      1 in 16

    • D. 

      1 in 4

    • E. 

      1 i n 6

  • 17. 
    Your patient's father died of Huntington's disease. Now the patient is 45 years old and asks you whether he can still get the disease. Two-thirds of all patients who carry the Huntington's gene already show signs of the disease by age 45, but your patient is still healthy. Based on this information, how likely is it that he will get the disease?
    • A. 

      1 in 2

    • B. 

      1 in 3

    • C. 

      1 in 9

    • D. 

      1 in 4 (Bayes’ Formula)

    • E. 

      1 in 6

  • 18. 
    A normal male mates with a female who is homozygous for an x‑linked recessive disorder. Of the offspring that they may have, it is probable that:
    • A. 

      No sons will be affected, and all daughters will be carriers

    • B. 

      All sons will be affected, and all daughters will be affected

    • C. 

      All sons will be affected, and all daughters will be carriers

    • D. 

      No sons will be affected, and all daughters will be affected all sons will be affected, and 1/2 the daughters will be carriers

  • 19. 
    What is the probability of having an affected child if one parent is affected with an autosomal recessive disease and the other parent is unaffected?
    • A. 

      1/4

    • B. 

      1/4 X 1/4 X 1/4

    • C. 

      Probability of the unaffected parent being a carrier X 1/2

    • D. 

      Pretty close to 100% because new mutations are frequent

    • E. 

      50% if the other parent is normal

  • 20. 
    Parents of a child with an autosomal recessive disease are:
    • A. 

      Likely to have mutations in different genes, locus heterogeneity

    • B. 

      Likely to have more affected sons than daughters

    • C. 

      Obligatory carriers

    • D. 

      Most likely homozygous normal and the disease was caused by a new mutation

    • E. 

      Not at risk of having another child with the disease

  • 21. 
    If one parent has an autosomal dominant disorder and is a heterozygote, what are the chances that they will have an affected offspring?
    • A. 

      1/4 X 1/4 X 1/4

    • B. 

      Pretty close to 100% because new mutations are frequent

    • C. 

      1/4

    • D. 

      50%, if the other parent is normal

    • E. 

      Probability of the unaffected parent being a carrier X 1/4

  • 22. 
    What is the probability that an offspring of an affected person and an unaffected person with an autosomal dominant disorder will be affected?
    • A. 

      1/3

    • B. 

      1/4

    • C. 

      2/3

    • D. 

      1/2

    • E. 

      Virtually 0

  • 23. 
    What proportion of all offspring are affected females if the father is affected with an X‑linked recessive disease and the mother is a carrier of the same disease?
    • A. 

      25%

    • B. 

      100%.

    • C. 

      75%

    • D. 

      50%

    • E. 

      Virtually 0

  • 24. 
    If an affected male mates with a normal female and has four offspring: one normal male, one affected male, and two affected female, the disease is MOST LIKELY inherited as:
    • A. 

      X linked dominant

    • B. 

      X linked recessive

    • C. 

      Autosomal dominant

    • D. 

      Autosomal recessive

    • E. 

      Y linked

  • 25. 
    If your mother was known to be a carrier of alpha‑antitrypsin deficiency, an autosomal recessive disorder, what is the probability that your child is also a carrier of this disease gene?
    • A. 

      1/4

    • B. 

      100%

    • C. 

      2/3

    • D. 

      1/2

    • E. 

      Virtually 0