DNA profiling - Lecture 4

Question 1

What is Huntington gene

Answer 1

Repeats certain genetic sequence - CAG
then damages neurones in certain area of brain

Question 2

What are grass snakes

Answer 2

Identification of new species in uk
Different species (natrix helvetica)

Question 3

How many types of snakes did DNA obtain

Answer 3

2 types of snakes

Question 4

Method of profiling

Answer 4

1. PCR enzymes used to produce fragments of DNA
   2.gel electrophoresis used to analyse the DNA samples
2. Gel then used to separate the fragments of DNA
3. More differences in pattern of bands would indicate snakes are different species

Question 5

Explain step 1of Extracting the DNA

Answer 5

Breaking up cells
Separate and expose cells to salt and soap
Soap helps -break down cellular and nuclear membranes to release the DNA
salt -helps bind DNA
Filtering off debris
Protein framework of chromosomes removed
Add ethanol-helps DNA precipitate

Question 6

Explain step 2 - gel electrophoresis

Answer 6

Allows to separate nucleotides based on size
DNA fragments - different size
Negatively charged because of phosphate group

Shorter fragments move faster then slower ones

Question 7

What is it used for

Answer 7

Criminal cases
Paternity cases
Medical diagnosis
Animals and plant breeding
Etc

Question 8

Give two features of DNA profile which lead to the identification of suspect being present at the scene of crime

Answer 8

Same position and thickness of bands

Question 9

DNA at crime scene is often found in small quantities
Chain reaction (PCR) is a technique that enables the analysis of these small samples of DNA
State how PCR makes this possible

Answer 9

Makes multiple copies
Amplifies DNA