DNA, the double helix that stores genetic information in a four-letter code

DNA (deoxyribonucleic acid) is the double-stranded helical molecule storing genetic information through sequences of four bases (A, T, G, C). The human genome contains 3.2 billion base pairs. Explore the full definition and applications on this page.

DNA is closely connected to genome and other Molecular Biology concepts. Understanding these relationships is essential for comprehensive knowledge in molecular biology and bioinformatics.

VigyanLLM's 24-step validated pipeline incorporates DNA as part of its rigorous quality control framework. The platform automates checks related to DNA to ensure primer design accuracy, specificity, and reliability for research and clinical applications.

DNA is a double helix composed of two polynucleotide strands running antiparallel. Each strand has a sugar-phosphate backbone with four nitrogenous bases: adenine (A), thymine (T), cytosine (C), and guanine (G). A pairs with T via two hydrogen bonds, and C pairs with G via three hydrogen bonds. The sequence of bases encodes genetic information.

DNA is double-stranded, uses deoxyribose sugar and thymine, and serves as the long-term genetic storage molecule. RNA is typically single-stranded, uses ribose sugar and uracil instead of thymine, and performs various functions including carrying genetic information (mRNA), catalyzing reactions (ribozymes), and regulating gene expression (miRNA, siRNA).

DNA replication is the process by which a cell copies its DNA before division. The double helix unwinds, and DNA polymerase synthesizes new complementary strands using each original strand as a template. The leading strand is synthesized continuously, while the lagging strand is synthesized in short Okazaki fragments that are later joined by DNA ligase.

A gene is a segment of DNA that contains the instructions for making a functional product, typically a protein or RNA molecule. Genes include coding regions (exons) that determine the protein sequence and non-coding regions (introns, promoters, enhancers) that regulate when, where, and how much of the product is made. The human genome contains approximately 20,000-25,000 protein-coding genes.

The DNA double helix is the three-dimensional structure of DNA, discovered by James Watson and Francis Crick in 1953 based on X-ray crystallography data from Rosalind Franklin and Maurice Wilkins. The structure explained how genetic information could be stored in the base sequence and accurately copied through complementary base pairing during replication.

Mitochondrial DNA (mtDNA) is a small circular DNA molecule found in mitochondria, inherited exclusively from the mother. It contains 37 genes essential for oxidative phosphorylation. mtDNA is used in evolutionary studies, forensic identification, and diagnosing mitochondrial disorders. It mutates faster than nuclear DNA, making it useful for tracing maternal lineages.

Modern DNA sequencing uses next-generation sequencing (NGS) technology. DNA is fragmented, adapters are ligated, and fragments are sequenced in parallel on a flow cell. Illumina sequencing uses fluorescently labeled reversible terminators that emit a signal when each base is incorporated. Oxford Nanopore sequencing measures electrical current changes as DNA passes through a protein nanopore.