Sanger Sequencing 2

What are the key components of nucleotides in Sanger sequencing?

A nucleotide consists of a nitrogenous base (A, T, G, C), a sugar residue, and a phosphate group.

What is the role of deoxynucleoside triphosphates (dNTPs) in DNA polymerization?

DNA polymerases use dNTPs as substrates, and the 3' hydroxyl group is crucial for DNA polymerization.

What happens if a dideoxynucleotide (ddNTP) is incorporated into a growing DNA strand during Sanger sequencing?

The reaction stops, preventing further elongation of the DNA strand.

How are DNA fragments separated in classical Sanger sequencing?

DNA fragments are separated by size using polyacrylamide gel electrophoresis.

What is the advantage of using fluorescent dyes in modern Sanger sequencing?

Each ddNTP is labeled with a different fluorescent dye, allowing for sequencing in a single tube.

What is the purpose of quality control in Sanger sequencing?

Quality control ensures the accuracy and reliability of sequencing data by checking template quality, primer design, reaction conditions, and data analysis.

What does bidirectional coverage in Sanger sequencing refer to?

The practice of sequencing both strands of the DNA template to ensure accuracy and reliability of the sequence data.

What are key considerations for primer selection in Sanger sequencing?

Specificity, length and composition, melting temperature (Tm), avoiding secondary structures, and positioning should all be taken into account.

How does modern Sanger sequencing improve upon classical Sanger sequencing methodologies?

Modern Sanger sequencing uses single-tube reactions with fluorescently labeled ddNTPs and typically employs capillary electrophoresis for better resolution.

What method is used to read the DNA sequence in modern Sanger sequencing?

The sequence is interpreted by analyzing the order of peaks in a chromatogram, corresponding to the specific terminal nucleotides.