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Genetics 301 Quiz #2
Spring 2003, Class week 3

  1. A woman with normal vision and hair pattern whose father was color blind (X-linked recessive) and bald (autosomal dominant in males, autosomal recessive in females) marries a man with normal vision who is not bald. (Assume that the woman’s father is homozygous for the bald allele and that her mother lacks the allele). What proportion of all of their offspring will be color blind males who will eventually be bald? Explain your result. (5 pts).
  2. The woman is heterozygous for both colorblindness and for baldness. Chance of being a male is (1/2), chance of being color blind if male is (1/2), chance of being bald is (1/2), product of all of the above is (1/8). Two points for the right answer (1/8) and one point each for each of the component probabilies.

     

     

     

  3. In a species with two pairs of chromosomes, how many different types of gametes would be produced by each sex, assuming that no crossing over took place? (2 pts.)
  4. If we treat one chromosome as being A type and the homolog at a type, and the other chromosome as B type with the homolog as b type, it is apparent that there are four possible types of gametes produced by each sex (AB, Ab, aB ab).

     

     

  5. Place the following events in meiosis in their correct order: (3 pts).
  1. Sister chromatids separate from each other
  2. Crossing over between homologous chromosomes
  3. Homologous chromosomes separate from each other.

 

Correct order:

b, c, a