DNA SEQUENCEING: ESSENCE, POSSIBILITIES AND APPLICATIONS
What is DNA sequencing?
DNA sequencing is the process of determining the exact sequence of nucleotides (A, T, C, G) in a DNA molecule. In other words, it is reading the genetic code of a person or any other organism. The method allows you to identify mutations, variations and genetic traits that affect health, disease risks, drug response, etc.
History and stages of technology development
1977 — development of the Sender method, which became the basis for the first genetic decodings.
2003 — completion of the Human Genome Project: complete human DNA decoded.
Today — used next generation sequencing (NGS), which allows the analysis of thousands of genes simultaneously with high speed and accuracy.
Sequencing methods
Sender sequencing — a classic method, still relevant for short fragments.
NGS (Next Generation Sequencing) — high-throughput technology used for whole-genome, exome, and panel sequencing.
Third generation (PacBio, Oxford Nanopore) — capable of reading long stretches of DNA in real time.
Indications for sequencing
Hereditary diseases
Oncological diagnostics
Prenatal genetic testing
Individualization of treatment (pharmacogenetics)
Unspecified conditions (e.g., developmental delay, epilepsy)
Examples from medical practice
Patient with suspected Marfan syndrome — a mutation was detected in the FBN1 gene.
In a child with autism — exome sequencing allowed us to detect a de novo mutation that was not known in the family.
In a cancer patient — NGS testing revealed a BRCA1 mutation, which changed the treatment plan.
Advantages and limitations
Advantages:
high accuracy and sensitivity;
the ability to analyze tens of thousands of genes at a time;
informativeness for diagnosing rare and complex diseases;
prognostic capabilities (identification of predispositions to diseases).
Limitation:
difficulty in interpreting some results;
the probability of detecting “variants of uncertain significance”;
high cost in some cases;
ethical dilemmas (e.g., whether to inform the patient of findings unrelated to his complaints).
Comparison table of sequencing methods
| Method | Precision | Speed | Read length | Data volume | Cost |
|---|---|---|---|---|---|
| Sanger | High | Slow | Up to 1000 pairs | Little | Medium |
| NGS | Very high | High | Short snippets (150–300) | Great | 1 gene lower |
| Third generation | Medium | Very high | Up to 1 million pairs | Very large | High |
Relevance for the future of medicine
DNA sequencing is gradually becoming a standard not only in complex clinical cases but also in personalized medicine. It is used in the selection of biological therapies, immunotherapy in oncology, risk prediction for diabetes, heart disease, neurological conditions. Genetic tests are becoming increasingly available, including commercial products for identifying ancestry or food intolerances.
DNA sequencing opens a new era in medicine, when treatment and prevention become individual, and the accuracy of diagnosis is maximized. It is not just an analysis - it is a map of our biological essence.
Director of Medi Lab Plus LLC, a doctor of the highest category. Has over 45 years of practical experience in medicine and laboratory diagnostics. Founder and head of the laboratory since 2007. More details…