Students will be asked to hand in all laboratory questions, charts and drawings. Each of these will be graded on a point basis. In addition students will be asked to complete a 30 point brochure and a 30 point quiz/test on material associated with this unit. A sample test with answers is attached at the end of this unit. 
 
 

Multiple Choice:
1. A normal human female has how many Barr bodies in her cells?
a. 0 b. 1 c. 2 d. 3

2. What can a calico cat not be?
a. mostly orange b. female c. male d. feline

3. If the results of an X-chromatin body test (Barr body) came out with 1 barr body in 15 percent
of the cells which one of the following could the patient be.
a. a normal female
b. a Klinefelter male
c. a Turner Female
d. both a and b

4. In the barr body the “fixative” step is for:
a. cleaning the slide
b. attaching the cells to the slide so they won’t wash away.
c. coloring the cells
d. rinsing stain off the cells and drying them.

5. Duchenne Muscular Dystrophy is caused by
a. an extra chromosome
b. an absent or mutated gene for a protein
c. a missing chromosome
d. an injury in early childhood

6. Duchenne Muscular Dystrophy is inherited in which way
a. Dominant
b. Recessive
c. Sex linked
d. Multiple alleles

7. The gene for the orange color in cats is carried on their
a. tail
b. Y chromosome
c. X chromosome
d. none of the above

8. A Genetic Counselor does what?
a. makes pedigrees
b. figures out the probability of more abnormal children
c. takes a family history
d. all of the above

9. The person who came up with the idea of random X inactivation is:
a. Ebstein Barr
b. Mary Barr
c. Mary Lyon
d. Aristotle

10. Who is more likely to get Duchenne Muscular Dystrophy.
a. a 7 year old boy
b. a 7 year old girl
c. an 18 year old boy
d. an 18 year old girl

Matching:
11. a combination of genetic karyotypes in A. Barr body one body

12. inactive chromatin (no transcribing of genes) B. Paternal

13. the inactive X chromosome C. Heterochromatin

14. an enzyme found in the blood of patients D. Creatinine phosphokinase with Duchenne Muscular Dystrophy

15. something inherited from your father E. Mosaic

Essay:
16-20. What are the genotypes and phenotypes of a mating between an all orange female cat and a black male cat. Give the sexes, colors and probability of all possible offspring. (Hint: Punnett Squares will be useful).

21-25. Using the information you have learned about the Lyon Hypothesis describe it to someone who has never heard of it before and then describe its role in the color of the Tortoise colored mouse. Be sure to describe the cytogenetics involved as well.

26-30. Would it ever be possible to have a male calico cat? Why and How? Hint: Take a
mutation in the embryo into consideration as a possibility.

The offspring will be half Calico females and half orange males
21-25. Important Points:

1. Females have two X’s - males have one
2. At a certain cell stage one is turned off inactivated for dosage compensation.
3. All females are then mosaic
4. The mouse color gene resulted from a translocation to the X chromosome
5. When the X turned off in females so did the color gene.
6. The tortoise color is then the result of a mosaic situation in females.
26-30. It is possible to get a male calico cat but it would be extremely rare. Possibilities
include:
1. A chimera where the embryo is actually twins with the cells coming together.
2. A mutation of the color gene in a later stage of embryogenesis.