Polydactyly

• What is a characteristic of polydactyly II?

  Extra fingers or toes
• What type of allele causes polydactyly II?

  Dominant allele
• Can a person be a carrier of the polydactyly allele?

  No, they will express the trait
• What are the genotypes of a heterozygous man and a homozygous normal woman in a cross?

  Man: heterozygous, Woman: homozygous normal
• What is the expected ratio of offspring in the cross between a heterozygous man and a homozygous normal woman?

  1:1 polydactyly to unaffected
• What does it mean that the offspring percentages are probabilities?

  All offspring could have either trait
• What is embryo screening used for?

  To test for inherited disorder alleles
• What happens to embryos that do not have defective alleles?

  They are implanted into the woman
• What is a major ethical concern regarding embryo screening?

  Destruction of healthy embryos
• What is a potential future use of embryo screening?

  To produce offspring with desirable features
• What is gene therapy?

  Correcting faulty alleles to treat disorders
• Is gene therapy currently widely used?

  No, it is still experimental
• What are the issues surrounding embryo screening?

  • Expensive process
  • Ethical concerns about embryo destruction
  • Potential for selecting desirable traits
• What two inherited disorders were discussed in the videos?

  • Cystic fibrosis
  • Polydactyly II
• What are the genotypes and phenotypes of the offspring from the cross between a heterozygous man and a homozygous normal woman?

  • Genotypes: 50% heterozygous, 50% homozygous normal
  • Phenotypes: 50% polydactyly, 50% unaffected