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Flashcards · Biology · Inheritance

Family Pedigrees

16 cards

  1. What does a square represent in a pedigree?

    A male.

  2. What does a circle represent?

    A female.

  3. What does a filled symbol mean?

    The person has the characteristic or disorder.

  4. What do the rows in a pedigree show?

    Generations.

  5. What does a horizontal line between two symbols show?

    The two people are partners.

  6. Two unaffected parents have an affected child. Is the allele dominant or recessive?

    Recessive.

  7. What are the genotypes of the parents in that case?

    Both are heterozygous carriers (Ff).

  8. What genotype does a person with cystic fibrosis have?

    ff.

  9. What is the chance that the child of two carriers has cystic fibrosis?

    1 in 4 (25%).

  10. What is the chance a child of an affected Huntington's parent (Hh) and an unaffected parent (hh) is affected?

    1 in 2 (50%).

  11. Is Huntington's disease caused by a dominant or a recessive allele?

    A dominant allele.

  12. Is polydactyly caused by a dominant or a recessive allele?

    A dominant allele.

  13. If a dominant condition affects a child, must at least one parent have it?

    Yes, unless a new mutation has occurred.

  14. What is genetic counselling?

    Advice about the chances of passing an inherited disorder to a child.

  15. Can you tell the genotype of an unaffected child of two carriers?

    No. It could be FF or Ff, so the pedigree shows it as unknown.

  16. Common mistake with pedigrees?

    Saying the allele is dominant because both parents are unaffected. Unaffected parents with an affected child mean recessive.