DNA Profiling

Question 1

Who developed DNA fingerprinting and in what year?

Answer 1

Alec Jeffreys in 1986

This development took place in England.

Question 2

What method is used in the lab for DNA fingerprinting?

Answer 2

RFLP—Restriction Fragment Length Polymorphism

This method involves several steps to analyze DNA.

Question 3

List the 6 steps of DNA fingerprinting.

Answer 3

• Extract DNA
• Cut DNA
• Separate DNA by size
• Southern Blot
• X-RAY picture
• Analyze data

Each step is crucial for obtaining a DNA fingerprint.

Question 4

What is the first step in the DNA fingerprinting process?

Answer 4

Extract DNA

DNA can be extracted from sources such as blood, semen, skin, or hair roots.

Question 5

How is DNA cut in the DNA fingerprinting process?

Answer 5

Using restriction enzymes that search for repeating “nonsense” segments of the DNA strand

Question 6

What technique is used to separate DNA by size?

Answer 6

Agarose gel electrophoresis

DNA fragments are placed in wells of an agarose gel and an electric charge is applied.

Question 7

What are the short fragments of DNA called?

Answer 7

STR (short tandem repeats)

Short travel faster

These fragments are separated by size during electrophoresis.

Question 8

What is the purpose of the Southern Blot in DNA fingerprinting?

Answer 8

To transfer DNA fingerprint from the gel to a nylon sheet

This process attracts the negatively charged DNA to the positively charged sheet.

Question 9

What is created when the Southern Blot is exposed to an X-RAY film?

Answer 9

AUTORAD

This is the final, readable product of the DNA fingerprinting process.

Question 10

What are restriction enzymes used for?

Answer 10

To cut DNA

They are extracted from bacteria and recognize specific sequences in the DNA.

Question 11

What are recognition sites in the context of restriction enzymes?

Answer 11

Specific sequences of nitrogen bases where DNA is cut

These sites are usually 4-8 nitrogen bases in length.

Question 12

True or false: Everyone has the same recognition sites in their DNA.

Answer 12

TRUE

However, the number of times these sites repeat varies among individuals.

Question 13

What factors account for the different DNA fingerprints among individuals?

Answer 13

• Mutations
• Deletions
• Genetic differences (eye color, blood type, etc.)

These variations contribute to the uniqueness of each person’s DNA.