Biology questions

  1. Cystic fibrosis is a recessive disorder. Neither Oliver or Karla have cystic fibrosis, but their son James does.
    Who among Oliver, Karla, and James is heterozygous for the cystic fibrosis allele? Who is homozygous?
  2. After completing your biology class, you feel like you have a better understanding of genetics. Then you see
    an article posted on social media talking about Huntington disease, a progressive neurological disorder. It links
    to a website that says that based on many years of research scientist and doctors saw that Huntington disease
    is a genetic disease that is inherited in a dominant pattern, meaning if a parent has the disease the child has a
    50:50 chance of inheriting it. But the author of this website found a family where all 8 children have Huntington
    disease. This, the author says, shows that science is all wrong about Huntington disease because if there is
    really a 50:50 chance of inheriting the disease, then only 4 of the children would have it. Is this article correct or
    not? Explain your answer
  3. In a shocking discovery, biologists discover dragons! Dragon geneticists determine that flame eyes (F) are
    dominant to blue eyes (f) and burbling (B) is dominant to whistling (b). They suspect that the two genes are
    linked in one of the autosomes. They mate a true-breeding, flame-eyed, burbling female with a true-breeding,
    blue-eyed, whistling male. They then mate a pair of the offspring. Assuming dragon genetics follows the same
    rules as fruit flies, what ratio of genotypes would you expect if the genes were not linked? (Remember you are
    crossing FfBb x FfBb). If the genes are linked, which of the following F2 genotypes will be rarer than would be
    expected if the genes were not linked?
  4. Analyze the pedigree below and determine if the trait is inherited as autosomal dominant, autosomal
    recessive, X-linked dominant, X-linked recessive, or Y-linked. Justify your answer

Sample Solution