Sylvia S. Mader; Biology
Reading Guide Chapter 12: Chromosomal Pattern of Inheritance
1) Of the 46 chromosomes found in humans, which are autosomes and which are sex chromosomes. How does the sex
chromosome configuration of males differ from females?
2) Which gamete determines the sex of the new individual? What are sex linked traits?
3) List four reasons fruit flies are the “perfect” organism to perform genetics studies on.
4) When Morgan crossed a red eyed fruit fly (RR) and a white eyed fruit fly (rr), he obtained the classic 3:1 ratio that
was expected, but all of the white eyed flies were male. Explain this phenomenon.
5) Cross a white eyed male fruit fly with a red eyed (heterozygous) female fruit fly. Show the punnett square and the
genotype and phenotype ratio. This is a x-linked trait.
6) List and briefly explain four human x-lined disorders.
7) What is gene linkage? What is a linkage map?
8) If the gene for antennae is 10 map units away from the gene for eye color in fruit flies, what would you predict the
frequency of crossing over to be?
9) Complete the practice problems on the bottom of page 211 (problems 2 and 3).
10) Describe polyploidy. What organisms exhibit polyploiydy?
11) Explain what a nondisjunction event is (during meiosis). Draw a picture of meiosis 1 to illustrate a nondisjunction
event occurring.
12) Briefly explain how a woman could end up with Turner’s syndrome (45 chromosomes).
13) Define deletion, translocation and duplication and draw an illustration of each.
14) Describe a syndrome that results from a deletion and a translocation.
15. Do an internet search of one genetic disorder (of your choice) and answer the following questions:
a) What is the name of the disorder?
b) What are the symptoms of the disorder?
c) Is this disorder x-linked? Nondisjunction? Autosomal recessive? Autosomal dominant?
d) What chromosome is altered?
e) What is the life expectancy of an individual with this disorder?
f) Have you ever heard of this disorder before?