STR Amplification
- Created by: AAntonianannetti
- Created on: 13-05-19 16:58
View mindmap
- STR Amplification
- What are STRs?
- Short Tandem Repeats
- Non-Coding repeating Sequences
- Found on a location of the chromosome
- Contain alleles
- One from each parent
- Non-Coding repeating Sequences
- Can help identify people as they are highly discriminative
- A large number of STR loci have been identified, but only around 20 are commonly analysed in forensic casework
- Short Tandem Repeats
- What is STR amplification?
- A simultaneous amplification of more than one locus
- STR Interpretation
- The dyes used to label the PCR products overlap and the raw data contains peaks that are composed of more than one dye colour
- Software used, calculates how much spectral overlap there is between each dye and subtracts this from the peaks within the profile
- DNA fragments are sized and genotypes are assigned
- Software used, calculates how much spectral overlap there is between each dye and subtracts this from the peaks within the profile
- The dyes used to label the PCR products overlap and the raw data contains peaks that are composed of more than one dye colour
- STR polymorphism detection
- After STR polymorphisms have been amplified during PCR, the length of the products must be precisely measured.
- This is done during electrophoresis
- Electrophoresis separates DNA molecules depending on their lengths
- Dyes can be used
- Electrophoresis separates DNA molecules depending on their lengths
- This is done during electrophoresis
- After STR polymorphisms have been amplified during PCR, the length of the products must be precisely measured.
- STR Interpretation
- A simultaneous amplification of more than one locus
- Structure of an STR
- Contain a core repeat region between 1bp and 6bp long and have alleles that are generally less than 350bp
- First used in the early 1990s.
- The UK Forensic Science Service developed the first STR-based typing system that was designed for forensic analysis in 1994
- Advantages of STRs
- Easily amplified by PCR and are suitable for degraded samples
- Highly vairable
- Commerical kits available which allows for multiplexing and standardisation
- Uniform set of core STR loci - creating national and international sharing of profiles
- Disadvantages of STRs
- Wide use of commercial kits means that the choice of STRs is restricted
- Not always useful for non European populations
- Creates bias
- Not always useful for non European populations
- Wide use of commercial kits means that the choice of STRs is restricted
- What are STRs?
Similar Biology resources:
Teacher recommended
Comments
No comments have yet been made