DNA profiling

DNA profiling:

• This is a technique used to analyse different DNA samples 
• It can be used for:
  • Forensic science
  • Maternity/ paternity disputes 
  • Analysis of disease

Polymerisation chain reaction:

• In order for the DNA to be analysed it must first be amplified using PCR 
• PCR is a cyclic reaction 
• Polymerisation chain reaction is a biotechnology used to amplify a short length of DNA into thousands of millions of copies 
• PCR is used for:
  • DNA profiling
  • Disease diagnosis 
  • Forensic science 
  • Gene therapy 
  • Determine taxonomic relationships between species 

Stages of PCR:

Reagents:

• Primers: short sequence of nucleotides that contain fluorescent labels which allow for better identification when DNA is amplified 
• Taq DNA polymerisation: catalyses assembly of DNA from dNTPs 
• Deoxynucleotide triposphates: contains bases that comprise the DNA 

Stages: 

1. DNA sample is obtained 

2. DNA sample is heated at 95°C, hydrogen bonds holding the double stranded DNA together are broken by process of denaturing, producing single stranded DNA (ssDNA)

3. Mixture is cooled at 55°C- 70°C

4. Allows primers can anneal (bind by hydrogen bonds) by complementary-base pairing to target regions of each of the ssDNA formed, this is known as annealing 

5. The binding of primers formes small…