PCR Amplifies Pieces of DNA

Question: If you detected 2 alleles using amplicon-length analysis, would you need to then perform repeat-primed PCR? Why or why not? Answer: PCR amplifies pieces of DNA across many orders of magnitude. As a result, thousands copies of the DNA is generated for any specific DNA sequences. Repeated primed PCR is used to generate amplicons because of many annealing sites present on the template. For screening of fragile X permutations, determination of mosaic fragile X samples, screening of full mutations, it is used. When a detection of allele is done by amplicon-length analysis, additional testing is to be done by carrying out repeated-primed Polymerase Chain Reaction, for confirming amplification of both the alleles. This is needed to be done in order to detect whether the alleles are heterozygous or homozygous. Detection of carrier can be done. This will lead to the identification of dominant and recessive alleles. Mutations present can be detected also. This is because amplification is done by PCR. Mutations are important for identification as mutations influence the working of the alleles immensely. The alleles are effected by such mutations. Repeat-primed PCR is highly specific for particular nucleotide sequences. Moreover, there are no false positives in this procedure. The method is errorless. The highly sensitive nature of the repeat-primed PCR makes it the choice of molecular technique. Amplification can be done from very minute amount of DNA.