Summary
Determining the order of bases, from Sanger chain termination to modern high-throughput methods.
In depth
Sanger (1977) uses dideoxy chain terminators with fluorescent labelling. Illumina sequencing by synthesis reads millions of short fragments. Nanopore sequencing detects current changes as DNA passes through pores.
Reads are assembled and aligned; coverage depth shows reliability. Error rates differ by platform. Variant calling identifies SNPs and indels.
Key idea: sequence data need computational analysis to become meaningful.
DNA sequencing reads the order of bases. Sanger sequencing (1977) uses dideoxynucleotides that stop chain extension, producing fragments of every length that are read by fluorescent labels; it is accurate for single reads of about 800 bases.
Next-generation methods read millions of fragments in parallel, and third-generation methods read single long molecules. Accuracy, read length, cost and throughput differ across platforms. Applications include diagnosing disease, tracking outbreaks, ancient DNA and species identification (barcoding).
Example: sequencing a virus genome reveals new variants.
Key idea: raw reads must be assembled and annotated with software to give meaning.
Frequently asked questions
What is DNA Sequencing?
Determining the order of bases, from Sanger chain termination to modern high-throughput methods.
Which area of biology covers DNA Sequencing, and how advanced is it?
DNA Sequencing is one of the 56 topics in Biotechnology & Genomics. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Next-Generation Sequencing, Long-Read Sequencing, Single-Cell Sequencing.
Can you give an example of DNA Sequencing?
Sequencing of tumour DNA guides treatment.
What should I learn before DNA Sequencing?
Work through the Beginner topics in Biotechnology & Genomics first, such as Biotechnology, Genetic Engineering, Selective Breeding, then return to DNA Sequencing. Intermediate topics assume the Beginner vocabulary.
What topics are related to DNA Sequencing?
The closest topics to DNA Sequencing are Next-Generation Sequencing, Long-Read Sequencing, Single-Cell Sequencing, Comparative Genomics. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand DNA Sequencing?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for DNA Sequencing. To practise the whole of Biotechnology & Genomics, use the Biotechnology & Genomics quiz.
How is DNA Sequencing different from Next-Generation Sequencing?
DNA Sequencing: Determining the order of bases, from Sanger chain termination to modern high-throughput methods. Next-Generation Sequencing: Massively parallel methods that read millions of DNA fragments simultaneously, cutting cost and time. Read both side by side and note what each one explains.
How should I study DNA Sequencing step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Next-Generation Sequencing and explain the difference aloud. Finally, take the Biotechnology & Genomics quiz and come back to this page for any question you miss.