DNA replication

In <a href="/facts/Molecular_biology/YgqU35ub">molecular biology</a>, DNA replication is the <a href="/facts/Biological_process/jpHldXz2">biological process</a> of producing two identical replicas of DNA from one original <a href="/facts/DNA/nB89Iauz">DNA</a> molecule. DNA replication occurs in all <a href="/facts/Life/DNw7NUId">living organisms</a>, acting as the most essential part of <a href="/facts/Heredity/t0aMmRWx">biological inheritance</a>. This is essential for <a href="/facts/Cell_division/n5MrunWj">cell division</a> during growth and repair of damaged tissues, while it also ensures that each of the new cells receives its own copy of the DNA. The cell possesses the distinctive property of division, which makes replication of DNA essential.
DNA is made up of a <a href="/facts/Nucleic_acid_double_helix/XHeMuslB">double helix</a> of two <a href="/facts/Complementary_DNA/P2nWeY4T">complementary</a> <a href="/facts/DNA_strand/nB89Iauz">strands</a>. DNA is often called double helix. The double helix describes the appearance of a double-stranded DNA which is composed of two linear strands that run opposite to each other and twist together. During replication, these strands are separated. Each strand of the original DNA molecule then serves as a template for the production of its counterpart, a process referred to as <a href="/facts/Semiconservative_replication/rJJAglA3">semiconservative replication</a>. As a result, the new helix will be composed of an original DNA strand as well as a newly synthesized strand. Cellular <a href="/facts/Proofreading_(Biology)/Fn8W2EhA">proofreading</a> and error-checking mechanisms ensure near perfect <a href="/facts/Fidelity/v0aRSvLu">fidelity</a> for DNA replication.
In a <a href="/facts/Cell_(biology)/bLM9UQvy">cell</a>, DNA replication begins at specific locations (<a href="/facts/Origin_of_replication/StuSWefk">origins of replication</a>) in the <a href="/facts/Genome/tjhWET4V">genome</a> which contains the genetic material of an organism. Unwinding of DNA at the origin and synthesis of new strands, accommodated by an <a href="/facts/Enzyme/DSI1Fh7y">enzyme</a> known as <a href="/facts/Helicase/IemubWzR">helicase</a>, results in <a href="/facts/Replication_fork/wrU6RuR3">replication forks</a> growing bi-directionally from the origin. A number of <a href="/facts/Protein/Jxmagu3E">proteins</a> are associated with the replication fork to help in the initiation and continuation of <a href="/facts/DNA_synthesis/ywV1plto">DNA synthesis</a>. Most prominently, <a href="/facts/DNA_polymerase/xtNLncBu">DNA polymerase</a> synthesizes the new strands by adding <a href="/facts/Nucleotide/pQKEwlJI">nucleotides</a> that complement each (template) strand. DNA replication occurs during the S-stage of <a href="/facts/Interphase/c37v07K4">interphase</a>.
DNA replication (DNA amplification) can also be performed <a href="/facts/In_vitro/evp3hAX6">in vitro</a> (artificially, outside a cell). DNA polymerases isolated from cells and artificial DNA primers can be used to start DNA synthesis at known sequences in a template DNA molecule. <a href="/facts/Polymerase_chain_reaction/G0jWzJy1">Polymerase chain reaction</a> (PCR), <a href="/facts/Ligase_chain_reaction/cWR4yY94">ligase chain reaction</a> (LCR), and <a href="/facts/Transcription-mediated_amplification/Kd3cVYUT">transcription-mediated amplification</a> (TMA) are examples. In March 2021, researchers reported evidence suggesting that a preliminary form of <a href="/facts/Transfer_RNA/pR9T5XSl">transfer RNA</a>, a necessary component of <a href="/facts/Translation_(biology)/JcPC1rth">translation</a>, the biological synthesis of new <a href="/facts/Protein/Jxmagu3E">proteins</a> in accordance with the <a href="/facts/Genetic_code/zUK0bY1B">genetic code</a>, could have been a replicator molecule itself in the very early development of life, or <a href="/facts/Abiogenesis/BvAmLPQP">abiogenesis</a>.

DNA replication open-in-new

DNA replication