Diagnostic DNA

Question 1

Annealing of a single-strand of DNA to a complementary strand of a different DNA molecule.

Answer 1

Hybridization

Question 2

The degree to which mismatches are tolerated in hybridization reaction.

Answer 2

Stringency

increased stringency = decreased mismatches

Question 3

A gel matrix that acts like a sieve, where the short fragments migrate the fastest (towards the anode). Nucleic acids are separated by their size and length.

Answer 3

Gel Electrophoresis

Question 4

What are the two major approaches for detecting specific DNA sequences in a complex mixture of DNA fragments?

Answer 4

1. Hybridization

2. PCR

Question 5

What determines the stringency by hybridization?

Answer 5

1. Temperature
2. Salt Concentration
3. Denaturing agents

Question 6

What are three types of gel electrophoresis?

Answer 6

S - Southern Blotting D - DNA
N - Northern Blotting R - RNA
O - ————————- O ————
Western Blotting P - Proteins

Question 7

What kind of disease can only be reliably detected by Southern Blotting and why?

Answer 7

Hemophilia A because the disease is a balanced rearrangement.

Question 8

How can we detect large deletions by Southern Blotting?

Answer 8

If the band has a weak intensity, this is indicative of less DNA (which is a deletion).

Question 9

If we are reading a Northern Blot sample, and we see there are bands of dark appearance - what does this represent?

Answer 9

The bands are darker because of an up-regulation of expression.

Question 10

What are some advantages of PCR?

Answer 10

• Faster
• Less DNA required
• No labeled probe required
• Cheaper