How Scientists First Made DNA Replicate in New Cells
This 1980 patent describes a method for cutting and pasting DNA pieces in a lab to create new, self-replicating genetic material that can be inserted into bacteria, a foundational technique for genetic engineering.
Original patent title: “Process for producing biologically functional molecular chimeras”
This 1980 patent describes a method for cutting and pasting DNA pieces in a lab to create new, self-replicating genetic material that can be inserted into bacteria, a foundational technique for genetic engineering. Granted to Leland Stanford Junior University in 1980 with 15 claims and 346 forward citations, and it is now in the public domain.
Coverage
What does this patent actually cover?
This patent details a process for creating 'biologically functional DNA' outside of a living cell, then introducing it into a microorganism, like bacteria, so it can make copies of itself and potentially produce specific proteins. The method involves cutting a circular DNA molecule (like a plasmid or virus DNA) into a linear piece with specific ends, then attaching another piece of DNA that contains a desired gene. This combined DNA, called a 'replicon,' is designed to be able to replicate within a host cell. The patent specifically mentions creating 'transformants' – cells that have successfully incorporated this new DNA. A key part is using a gene for a 'phenotypical trait,' like resistance to a substance, to easily identify the modified cells from the original ones. For example, claimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 4 describes using resistance to a growth-inhibiting substance to select for bacteria that have taken up the new DNA.
The gap
What does this patent NOT cover?
- Does not cover methods where the DNA is not prepared 'in vitro' (in a lab).
- Does not cover DNA segments that do not contain an intact 'replicon' (the part needed for self-replication).
- Does not cover inserting DNA into organisms other than unicellular ones like bacteria.
- Does not cover the use of DNA segments that cannot be 'ligated' or joined together by their ends.
- Does not cover the production of proteins in organisms that naturally exchange genetic information with the source of the gene.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The innovation was in precisely cutting and joining different DNA fragments in a controlled, in-vitro manner to create a functional, self-replicating unit that could then be reliably introduced and selected for within a host organism.
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Production of recombinant human insulin
Manufacturing of monoclonal antibodies
Development of genetically modified crops
Research using E. coli as a host organism
Enzyme production for industrial processes
Why it matters
The bigger picture
This patent represents a cornerstone of modern biotechnology. It describes the fundamental technique of recombinant DNA technology, allowing scientists to insert specific genes into microorganisms. This capability paved the way for producing vital medicines like insulin and human growth hormone, developing genetically modified crops, and countless other applications in research and industry.
Filed
January 4, 1979
Granted
December 2, 1980
Market context
Who's building on this
Companies in this space
The foundational principles described here are universally applied across the biotechnology and pharmaceutical industries. Major companies like Genentech (a pioneer in the field), Amgen, and Pfizer, as well as countless academic labs and smaller biotech startups, rely on these core recombinant DNA techniques for drug development and biological research.
Market impact
This patent, and the technology it describes, essentially created the modern genetic engineering industry. It enabled the mass production of therapeutic proteins, transforming the treatment of diseases like diabetes and dwarfism, and laid the groundwork for the entire field of synthetic biology and modern agricultural biotechnology.
Claim 1 — Plain English
What this patent covers
This patent details a process for creating 'biologically functional DNA' outside of a living cell, then introducing it into a microorganism, like bacteria, so it can make copies of itself and potentially produce specific proteins. The method involves cutting a circular DNA molecule (like a plasmid or virus DNA) into a linear piece with specific ends, then attaching another piece of DNA that contains a desired gene. This combined DNA, called a 'replicon,' is designed to be able to replicate within a host cell. The patent specifically mentions creating 'transformants' – cells that have successfully incorporated this new DNA. A key part is using a gene for a 'phenotypical trait,' like resistance to a substance, to easily identify the modified cells from the original ones. For example, claim 4 describes using resistance to a growth-inhibiting substance to select for bacteria that have taken up the new DNA.
The clever bit
The innovation was in precisely cutting and joining different DNA fragments in a controlled, in-vitro manner to create a functional, self-replicating unit that could then be reliably introduced and selected for within a host organism.
What it does not cover
- Does not cover methods where the DNA is not prepared 'in vitro' (in a lab).
- Does not cover DNA segments that do not contain an intact 'replicon' (the part needed for self-replication).
- Does not cover inserting DNA into organisms other than unicellular ones like bacteria.
- Does not cover the use of DNA segments that cannot be 'ligated' or joined together by their ends.
- Does not cover the production of proteins in organisms that naturally exchange genetic information with the source of the gene.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
This patent is in the public domain
See the Freedom to Build guide — what is free to use, what is not, and how to cite this patent.
PatentBrief Score
Impact Score
Strong
Citation count
40/40
Highly cited
Claim breadth
10/20
Broad claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
0/20
Older than 20 years
Assignee scale
20/20
Major company or institution
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$60K – $192K
Midpoint $120K · expired or expiring · industry ×1.6
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Patent Claims
0 independent claims · 1 dependent
Claims are the legal boundaries of the patent. An independent claim stands alone. A dependent claim adds limitations to its parent, narrowing — but not broadening — the scope.
The original legal language
Original claims
15 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Boyer, H. W., & Cohen, S. N. (1980). How Scientists First Made DNA Replicate in New Cells (U.S. Patent No. 4,237,224). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/4237224/cohen-boyer-recombinant-dna
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How Scientists First Made DNA Replicate in New Cells cover?
This 1980 patent describes a method for cutting and pasting DNA pieces in a lab to create new, self-replicating genetic material that can be inserted into bacteria, a foundational technique for genetic engineering.
Who owns patent US 4237224?
Leland Stanford Junior University owns this patent, granted in 1980.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 4237224 cited by?
This patent has been cited by 346 later patents that build on its ideas.
What problem does this patent solve?
This patent represents a cornerstone of modern biotechnology. It describes the fundamental technique of recombinant DNA technology, allowing scientists to insert specific genes into microorganisms. This capability paved the way for producing vital medicines like insulin and human growth hormone, developing genetically modified crops, and countless other applications in research and industry.
What does this patent NOT cover?
Does not cover methods where the DNA is not prepared 'in vitro' (in a lab).
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