Final answer:
A single unique DNA sequence can generally be amplified using primers that are 20-25 nucleotides long. A set of three nucleotides, called a codon, codes for a single amino acid, thus a combination of 4³ or 64 codons is sufficient for all 20 amino acids. PCR techniques, developed by Kary B. Mullis, employ these primers to exponentially amplify specific DNA sequences.
Step-by-step explanation:
Amplification of Unique DNA Sequences
To amplify a single unique sequence of DNA, oligonucleotides, or primers, must be designed to match the ends of the target sequence. A primer length of 20-25 nucleotides is typically sufficient for specificity in Polymerase Chain Reaction (PCR) assuming all bases occur at an equal frequency. For coding a single amino acid, a set of three nucleotides, known as a codon, is necessary. Each codon specifies one amino acid, and since there are 4 possible bases, the combination of three bases (4³) allows for 64 possible codons, more than enough to encode all 20 amino acids.
The concept of PCR amplification is that the number of DNA sequences doubles with each cycle. Starting with a minimum of 100 DNA molecules, after 'n' cycles, there will be 2¹⁰ of the desired DNA sequence. This exponential increase enables the specific amplification and detection of DNA fragments even from a single cell or tiny fossil samples. The PCR technique, developed by Kary B. Mullis, has become a foundation for many areas of biological research and applied science.
When selecting primers for PCR, they should be in the range of 20-25 nucleotides in length to ensure specificity and a sufficiently high melting temperature for stable hybridization with the targeted DNA strands. The mass concentration of DNA is often measured in ng/mL, which is critical for determining the amount of DNA to be used in PCR reactions.