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4. The diagram below outlines a molecular test to determine if individuals have the sickle-cell allele. First the region is amplified by PCR and then digested with a restriction enzyme. The two primers are located just to the left of the “1” site and just to the right of the “3” site.
a. If the distance between site 1 and 2 is 250bp and the distance between site 2 and 3 is 500bp, then show what the gel would look like when the PCR product is cut with the restriction enzyme (show the bands in the empty gel above for people who are homozygous and heterozygous for these alleles)(2marks).
b. Which particular restriction enzyme is used for this RFLP analysis? How can this enzyme differentiate between individuals who have the wild type allele and the sickle cell allele (show the two different sequences)(2 marks)?


diagram attached *