1. At what temperature does polymerase copy the DNA during a PCR reaction
2. How many fragments containing your target sequence will you have after 30 cycles?
a. 3
b. 30
c. 1000
d. One million
e. Over one billion
3. What are the bands that appear in the gel?
4. Which fragment will move the farthest on a gel ("bp" stands for base pairs -
a longer fragment will have more base pairs).
a. 5000 bp
b. 3000 bp
c. 2000 bp
d. 1000bp
5. Use a Punnett square to determine the possible genotypes of Mr. and Mrs. Smith's unborn child (remember that DMD is a sex-linked trait)
Mr. Smit and Mrs. Smith genotype
Case Background
Mary and John Smith have three children: Daniel, age 5, Alice, age 4, and Michael, age 1. Mary and John noticed that Daniel was having difficulty climbing the stairs and complained about being extremely tired after playing tag with his sister. The family doctor ordered several tests on Daniel, which confirmed he had a disease called Duchenne Muscular Dystrophy (DMD). DMD is a genetic disease that results from damage to a gene on the X-chromosome. DMD is more common among males, and they inherit the defective copy of the gene from their mother. Individuals with DMD usually appear healthy until the age of four or five, when their muscles start to weaken. The doctor told Mr. and Mrs. Smith that Daniel would probably need a wheelchair within a few years and would probably die before reaching his 21st birthday.The Smiths became concerned about their remaining children, and wondered about their chances for developing DMD. Mr. Smith is clearly not affected by DMD, but Mrs. Smith must be a carrier for the disease; therefore, there is a chance that Michael will also be affected. Although
Alice could not have DMD, she could be a carrier. Mary has just found out that she is pregnant again and is also concerned about her unborn child being affected (if male) or a carrier (if female).