Family Trees

    Cards (18)

    • What should you be able to do by the end of the video on family trees?
      Interpret information from family trees
    • Why can interpreting family trees be tricky?
      You might need to watch the video multiple times
    • What type of allele causes cystic fibrosis?
      Recessive allele
    • What must a person inherit to have cystic fibrosis?
      Faulty allele from both parents
    • What genotype does a carrier of cystic fibrosis have?
      One copy of the faulty allele
    • How many copies of the faulty allele does a person with cystic fibrosis have?
      Two copies of the faulty allele
    • What type of allele causes polydactyly?
      Dominant allele
    • How many copies of the faulty allele must a person inherit to develop polydactyly?
      One copy from one parent
    • What does a family tree show regarding phenotypes and genotypes?
      Shows phenotypes, not genotypes
    • What is the genotype of person 2 who has cystic fibrosis?
      Lowercase e lowercase e
    • What evidence supports that cystic fibrosis is caused by a recessive allele?
      Person 11 has cystic fibrosis, parents do not
    • What would happen if cystic fibrosis was a dominant trait?
      At least one parent would have cystic fibrosis
    • What is the probability that persons 7 and 8 will have another child with cystic fibrosis?
      25% chance
    • What is the genotype of person 3 who has polydactyly?
      Capital P lowercase P
    • Why can't person 3 inherit the polydactyly allele from person 1?
      Person 1 does not have polydactyly
    • What is the probability that persons 6 and 7 will have a child with polydactyly?
      50% chance
    • What are the key characteristics of cystic fibrosis and polydactyly inheritance?
      • Cystic fibrosis: caused by a recessive allele
      • Requires two copies of the faulty allele
      • Polydactyly: caused by a dominant allele
      • Requires only one copy of the faulty allele
    • How do you use a Punnett square for cystic fibrosis and polydactyly?
      • Cystic fibrosis: two carriers (e.g., eE x eE) yields 25% chance
      • Polydactyly: one affected parent (e.g., Pp x pp) yields 50% chance