BRAINCAKEDNA Sequencing
DNA sequencing means working out the order of bases (A, T, C and G) in a piece of DNA. The classic method is Sanger sequencing, also called the chain termination method.
The DNA to be sequenced is mixed with:
• a primer
• DNA polymerase
• normal free DNA nucleotides
• a small amount of each of four terminator nucleotides (dideoxynucleotides), each with a different coloured fluorescent label. A terminator nucleotide lacks the -OH group needed to attach the next nucleotide, so when one is added, the new strand stops growing.
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Key terms in this lesson
- capillary electrophoresis
- A technique that separates DNA fragments by size as they move through a narrow, gel-filled tube under an electric current.
More in Gene Sequencing
- The Genome
- The Polymerase Chain Reaction
- How PCR Works
- Using DNA Sequencing
- Using DNA Sequencing to Manage Disease
- Introns and Satellite DNA
- DNA Profiles
- Gel Electrophoresis
All 12 lessons in Gene Sequencing · All Edexcel A-level Biology topics