DNA sequencing
Determining the order of nucleotides in DNA.
DNA sequencing is the method used to determine the exact order of nucleotides in a DNA molecule. This involves identifying the sequence of the four bases—adenine, thymine, cytosine, and guanine—through various technologies. The development of fast sequencing techniques has significantly advanced biological and medical research.
Knowing DNA sequences is essential for fundamental biology, genographic projects, and many applied fields like medical diagnostics, biotechnology, forensics, virology, and biological systematics. By comparing healthy and mutated DNA sequences, doctors can diagnose diseases such as various cancers, characterize antibody repertoires, and guide treatment decisions. Rapid sequencing enables more personalized medical care and helps identify and catalog more organisms.
The first DNA sequences were obtained in the early 1970s using labor-intensive two-dimensional chromatography. After fluorescence-based methods and automated DNA sequencers emerged, sequencing became much easier and exponentially faster.
**Applications** DNA sequencing can determine the sequence of individual genes, larger genetic regions like operons, entire chromosomes, or whole genomes of any organism. It is also the most efficient way to indirectly sequence RNA or proteins by analyzing their open reading frames. Sequencing has become a key technology in biology, medicine, forensics, and anthropology.
**Molecular Biology** In molecular biology, sequencing is used to study genomes and the proteins they encode. The information helps researchers identify changes in genes and noncoding DNA, including regulatory sequences, link these changes to diseases and traits, and find potential drug targets.
**Evolutionary Biology** Because DNA passes information between generations, sequencing helps evolutionary biologists understand how organisms are related and how they evolved. In February 2021, scientists reported sequencing DNA from animal remains—a mammoth—that was over a million years old, the oldest DNA sequenced to date.
**Metagenomics** Metagenomics identifies organisms in environments such as water, sewage, soil, air filters, or swab samples from living things. Knowing which microbes are present is crucial for ecology, epidemiology, and microbiology. Sequencing reveals which types of microbes exist in a microbiome.
**Virology** Since most viruses are too small to see wi
- number of unique viral sequences in GenB
- over 2.3 million
Lore & Background
The first DNA sequences were obtained in the early 1970s by academic researchers using laborious methods based on two-dimensional chromatography. Following the development of fluorescence-based sequencing methods with a DNA sequencer, DNA sequencing became easier and orders of magnitude faster. Knowledge of DNA sequences has become indispensable for basic biological research, DNA Genographic Projects, and in numerous applied fields such as medical diagnosis, biotechnology, forensic biology, virology, and biological systematics.
Reader's Guide
DNA sequencing has transformed biology and medicine by enabling the determination of individual genes, larger genetic regions, full chromosomes, or entire genomes. It allows researchers to identify changes in genes and noncoding DNA, associations with diseases and phenotypes, and potential drug targets. In evolutionary biology, sequencing helps study how organisms are related and how they evolved. In virology, it is a main tool to identify and study viruses, including estimating when a viral outbreak began using a molecular clock technique. Medical technicians use sequencing to determine risk of genetic diseases, diagnose rare diseases, and guide antibiotic treatments. Forensic investigation uses DNA sequencing along with DNA profiling for identification and paternity testing. The technology continues to evolve, with next-generation sequencing surpassing traditional Sanger sequencing as the most popular approach for generating viral genomes as of 2019.
Did You Know?
- The first DNA sequences were obtained in the early 1970s using two-dimensional chromatography.
- In February 2021, scientists reported sequencing DNA from a mammoth over one million years old, the oldest DNA sequenced to date.
- During the 1997 avian influenza outbreak, viral sequencing determined the influenza subtype originated through reassortment between quail and poultry.
- As of 2019, next-generation sequencing had surpassed traditional Sanger as the most popular approach for generating viral genomes.
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