Genetic Variation and Disease I Flashcards
1
Q
What are the two types of mutations?
A
- Germline - gamete-related
- Somatic - body cell related
2
Q
What does it mean for a mutation to be de novo?
A
NO FAMILY HISTORY
3
Q
Define the following terms
- MUTATION
- ALLELE
- POLYMORPHIC
A
- MUTATION - Changes in DNA sequence
- ALLELE - Single genes differing between individuals
- POLYMORPHIC - A locus with more than one allele
4
Q
What are the effects of promoter mutations?
A
- Decrease DNA Polymerase affinity for promoter site
- Decreased mRNA and protein production
5
Q
What is the effect of splice site mutations?
A
- Alter splicing signal used to splice introns
- Can result in accidental splicing of exons away from splice site
6
Q
Describe RFLP analysis.
A
- Isolation of nucleated cells in a sample
- Purify DNA and digest it with restriction enzymes
- Separate fragments by electrophoresis
- Transfer DNA to membrane by southern blotting and perform hybridisation
7
Q
What are the advantages and disadvantages of RFLP analysis?
A
- ADVANTAGES - Cheap and easy to do
- DISADVANTAGES - Time-consuming, requires large amounts of DNA ,hard to transfer DNA to membrane
8
Q
Describe PCR
A
- Similar steps to RFLP Analysis but after electrophoresis, thermocycle the mixture
- Stain the thermocycled mixture with dyes so can be visuallised
9
Q
What are the advantages and disadvantages of PCR?
A
- ADVANTAGES - Cheap, easy to do, small amounts of DNA needed
- DISADVANTAGES - Time-consuming, dyes used in staining can be carcinogenic
10
Q
Describe rtPCR
A
- Exact same steps as PCR
- But before thermocycling, measure the yield through spectrophotometry
11
Q
What are the advantages and disadvantages of rtPCR?
A
Same as those for PCR
12
Q
Describe dideoxysequencing (i.e Sanger sequencing)
A
- Complete PCR
- Load samples onto acrylamide gel
- Separate nucleotides by gel electrophoresis
13
Q
What are the advantages and disadvantages of Sanger sequencing?
A
- ADVANTAGES - requires small amounts of DNA
- DISADVANTAGES - hard to do, expensive, time-consuming, data produced can be unclear
14
Q
Describe next-generation sequencing
A
- Extract DNA and cut into fragments
- Cap fragments using adaptors and amplify the capped templates
- Sequenced using fluorescent nucleotides
- Compared to reference genome
15
Q
What are the advantages and disadvantages of next-generation sequencing?
A
- ADVANTAGES - requires small amounts of DNA, quick and cheap
- DISADVANTAGES - Reference genome required, capping adaptors have to be designed
