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Short tandem repeats (STRs) are short sequences of DNA, usually 2 to 7 base pairs - AQA - A-Level Biology - Question 9 - 2023 - Paper 2
Question 9
Short tandem repeats (STRs) are short sequences of DNA, usually 2 to 7 base pairs. STRs are repeated a number of times, one after another. For example, the STR D5581... show full transcript
Worked Solution & Example Answer:Short tandem repeats (STRs) are short sequences of DNA, usually 2 to 7 base pairs - AQA - A-Level Biology - Question 9 - 2023 - Paper 2
Step 1
Describe how STRs could be removed from a sample of DNA.
Answer
To remove STRs from a sample of DNA, restriction endonucleases or enzymes can be used. These enzymes cut DNA at specific base sequences or pairs, effectively targeting the STRs for removal. This process can also involve cutting at recognition or restriction sites.
Step 2
Explain the importance of knowing these base sequences in PCR.
Answer
Knowing the base sequences surrounding the STRs is crucial in PCR as they serve as primer binding sites. Primers are short sequences of DNA that provide a starting point for DNA synthesis in the amplification process. They ensure that the correct region of DNA is amplified, allowing for precise analysis of STRs.