Genetics, Part 2: Chromosomes Review Questions

1. What is a map unit in genetics? answer
2. List the characteristics of X-linked recessive inheritance. answer
   
   Use the information below to answer the next two questions
        G = gray body                      R = red eyes
        g = black (ebony) body         r = purple eyes
3. If the body color and eye color alleles are unlinked, what ratio of offspring would you expect from the cross: GgRr X ggrr? answer
4. If the body color and eye color alleles are linked, what ratio of offspring would you expect from the cross GgRr X ggrr (assume no crossing over)? answer

5. How many autosomes and sex chromosomes are there in humans? What letters are typically used to designate the sex chromosomes? answer

6. If any of the autosomes are present in one copy (monosomy), the condition is fatal. However, monosomy X is survivable. Explain why females can live with only one X chromosome. answer

7. How many X chromosomes are present in the cells of a female that has 2 Barr bodies? 3 Barr bodies? answer

8. How many X chromosomes are present in the cells of a male that has 2 Barr bodies? 3 Barr bodies? answer