{
  "patent_number": "US 4683202",
  "country": "US",
  "title": "How to Make Many Copies of a Specific DNA Segment",
  "original_title": "Process for amplifying nucleic acid sequences",
  "summary": "This patent describes the fundamental three-step process for making millions of copies of a specific piece of DNA using short starter molecules and an enzyme, a technique known as Polymerase Chain Reaction (PCR).",
  "what_it_does": "This patent details a process to amplify, or make many copies of, a specific nucleic acid sequence. First, two short DNA pieces called \"oligonucleotide primers\" attach to opposite ends of the target DNA (Claim 1a). An enzyme then builds new DNA strands starting from these primers, creating \"extension products.\" Next, these newly made DNA strands are separated from their original templates, often by heating (Claim 1b, 3, 4). Finally, the separated single strands are again treated with the same primers and enzyme to build more new strands (Claim 1c). This cycle of separating and rebuilding is repeated multiple times (Claim 2), creating an exponentially increasing number of copies of the target DNA. For example, if you wanted to copy a specific gene from a human DNA sample, you would design primers that match the beginning and end of that gene, then run these cycles to produce millions of copies.",
  "what_it_does_not_cover": [
    "Does not cover methods that amplify DNA without using two distinct oligonucleotide primers for each strand of the target sequence.",
    "Does not cover amplification processes that do not involve separating the primer extension products from their templates.",
    "Does not cover methods where the extension product synthesized from one primer cannot serve as a template for the synthesis of the other primer's extension product.",
    "Does not cover amplification techniques that do not repeat the separation and extension steps at least once.",
    "Does not cover direct amplification of RNA without an initial reverse transcription step to convert it to DNA, even though reverse transcriptase is mentioned as an enzyme option for RNA templates (Claim 7)."
  ],
  "filed": "1985-10-25",
  "granted": "1987-07-28",
  "expires": "2005-10-25",
  "status": "expired",
  "holder": "Cetus Corp",
  "holder_url": "https://patentbrief.org/company/cetus-corp",
  "inventors": [
    {
      "name": "Kary B. Mullis",
      "url": "https://patentbrief.org/inventor/kary-b-mullis"
    }
  ],
  "times_cited": 7558,
  "tags": [
    "biotech",
    "pharmaceutical",
    "diagnostics",
    "gene_editing",
    "research_tools",
    "forensic_science"
  ],
  "abstract": "The present invention provides a process for detecting the presence or absence of at least one specific nucleic acid sequence in a sample or distinguishing between two different nucleic acid sequences in said sample, wherein each nucleic acid sequence to be detected consists of two separate strands, which process comprises amplifying the specific sequence or sequences (if present) by (a) treating the sample with one oligonucleotide primer for each of the two strands of each different specific nucleic acid sequence being detected under hybridizing conditions such that for each strand of each different sequence being detected an extension product of each primer is synthesized which is complementary to each nucleic acid strand, wherein said primers are selected so as to be substantially complementary to each strand of each specific sequence such that the extension product synthesized from one primer, when it is separated from its complement, serves as a template for synthesis of an extension product of the other primer; (b) treating the product of step (a) under denaturing conditions to separate the primer extension products from their templates; (c) treating the product of step (b) with oligonucleotide primers such that a primer extension product is synthesized using each of the single strands produced in step (b) as a template; and detecting the thus amplified sequence or sequences (if present).",
  "url": "https://patentbrief.org/patent/us/4683202/pcr-polymerase-chain-reaction-mullis",
  "markdown_url": "https://patentbrief.org/patent/us/4683202/pcr-polymerase-chain-reaction-mullis/md",
  "google_patents_url": "https://patents.google.com/patent/US4683202",
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}