Cytogenetic techniques

Question 1

Southern blotting

Answer 1

• widely used method for the detection of a specific sequence in DNA
• developed by Dr Southern

Question 2

Western blotting

Answer 2

• widely used method for the detection of specific protein after electrophoresis
• sample is electrophoresed on a polyacrylamide gel and then blotted to a membrane
• membrane is incubated with the antibody to the specific protein

Question 3

Northern blotting

Answer 3

-detection method for specific RNA after electrophoresis

Question 4

Polymerase chain reaction

Answer 4

• minute amounts of DNA can be amplified using PCR
• uses oligonucleotide primers complementary to the sequences at each end of the DNA of interest
• the exact DNA sequence is amplified
• double stranded DNA is denatured by heat to single stranded, then cooled so that annealing can occur (primers bind to target DNA
• DNA polymerase is used to extend the primers and cycling happens

Question 5

FISH

Answer 5

• fluorescent in situ hybridisation
• FISH is a cytogenetic technique to detect and localise specific DNA sequences on chromosomes
• it uses fluorescent probes that bind to only those parts of the chromosome with which the probes have a high degree of sequence similarity
• fluorescence microscopy is employed to detect the location where the fluorescent probe binds to the chromosome

Question 6

DNA cloning

Answer 6

-plasmid is bacterial DNA which independently replicates

these can be used to replicate human DNA fragments