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 man who is heterozygous for the polydactyly allele?

  One polydactyly allele and one normal allele
• What are the genotypes of a woman who is homozygous for the normal allele?

  Two normal alleles
• What is the expected ratio of offspring in the cross between a heterozygous man and a homozygous normal woman?

  1 to 1 ratio
• What percentage of the offspring will have polydactyly from the described cross?

  50%
• What does it mean that the ratios in genetic crosses are probabilities?

  Outcomes can vary in actual offspring
• What is embryo screening used for?

  To test for inherited disorders
• 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 application of embryo screening?

  Producing offspring with desirable features
• What is gene therapy?

  Correcting faulty alleles to treat disorders
• Is gene therapy currently a standard treatment?

  No, it is still experimental