Describe how STRs could be removed from a sample of DNA.

Genetic fingerprinting using STRs requires amplification of the STRs using the polymerase chain reaction (PCR). The short base sequences either side of a specific STR are known.

Explain the importance of knowing these base sequences in PCR.

A single STR molecule consisting of a 12 base pair sequence of AGAT was amplified 50 times using PCR.

Calculate the total number of base pairs in all the STR molecules after 50 cycles of PCR.

Show your working.

Answer ______________

During genetic fingerprinting, the different STRs are separated by gel electrophoresis.

Give two features of STRs which enable them to be separated by gel electrophoresis.

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