How to Make Hybrid DNA and Grow It in Microbes
This patent describes the foundational method for cutting and pasting DNA from different sources to create new, functional DNA molecules, then inserting them into single-celled organisms like bacteria to make copies or produce new proteins.
Original patent title: “Process for producing biologically functional molecular chimeras”
What this patent covers
The actual claim
The patent details a method for creating "biologically functional DNA" (recombinant DNA) and getting a single-celled organism to replicate it. First, a circular piece of DNA, like a plasmid from a bacterium or a virus, is cut into a straight line (Claim 1a). This cut piece has special ends, called "termini," that are designed to stick to other DNA. Next, a "foreign" gene (a piece of DNA from a different source) is cut with matching ends and then "combined" with the first piece, essentially gluing them together (Claim 1b). This new, combined DNA is then put into a "unicellular organism," such as E. coli bacteria (Claim 2, 5). The patent explains how to select the organisms that successfully took up the new DNA by giving the DNA a "phenotypical trait," like resistance to a growth-inhibiting substance (Claim 4). These modified organisms then grow and make copies of the new DNA, or even produce proteins from the foreign gene (Claim 12). For example, one could insert the human insulin gene into a bacterial plasmid, transform bacteria with it, and then grow those bacteria to produce human insulin.
What this patent does NOT cover
The boundaries
- Does not cover methods for creating recombinant DNA inside a living organism, as it specifies "prepared in vitro" (Claim 1).
- Does not cover inserting DNA into multicellular organisms or complex eukaryotic cells, as it specifies "unicellular organisms" (Claim 1).
- Does not cover methods that do not involve cleaving and ligating DNA segments with "ligatable termini" (Claim 1b).
- Does not cover methods of selection that do not rely on a "phenotypical trait" imparted by the new DNA (Claim 1).
- Does not cover methods where the inserted gene is from the same organism and would naturally exchange genetic information (Claim 11).
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The novelty lay in the precise, controlled method of cutting DNA from different sources using "restriction enzymes" to create "cohesive ends" (Claim 8), then joining these pieces together with "enzymatic ligation" (Claim 7), and finally introducing this new hybrid DNA into a living cell to replicate and express the foreign gene. The key was making the foreign DNA functional within a new host and having a way to identify the successful modifications.
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
Industrial production of human insulin
Production of human growth hormone
Manufacturing of enzymes for detergents or food processing
Creation of genetically modified microorganisms for bioremediation
Development of vaccines using recombinant proteins
Why it matters
The bigger picture
This patent, often referred to as the "Cohen-Boyer patent," is a landmark in biotechnology. It describes the fundamental techniques for recombinant DNA technology, which allowed scientists to combine genetic material from different species. This breakthrough enabled the industrial production of vital proteins like human insulin, growth hormone, and various enzymes, transforming the pharmaceutical and agricultural industries. It laid the groundwork for gene therapy and many modern biological research tools.
Filed
January 4, 1979
Granted
December 2, 1980
Claim 1 — Plain English
What this patent covers
The patent details a method for creating "biologically functional DNA" (recombinant DNA) and getting a single-celled organism to replicate it. First, a circular piece of DNA, like a plasmid from a bacterium or a virus, is cut into a straight line (Claim 1a). This cut piece has special ends, called "termini," that are designed to stick to other DNA. Next, a "foreign" gene (a piece of DNA from a different source) is cut with matching ends and then "combined" with the first piece, essentially gluing them together (Claim 1b). This new, combined DNA is then put into a "unicellular organism," such as E. coli bacteria (Claim 2, 5). The patent explains how to select the organisms that successfully took up the new DNA by giving the DNA a "phenotypical trait," like resistance to a growth-inhibiting substance (Claim 4). These modified organisms then grow and make copies of the new DNA, or even produce proteins from the foreign gene (Claim 12). For example, one could insert the human insulin gene into a bacterial plasmid, transform bacteria with it, and then grow those bacteria to produce human insulin.
The clever bit
The novelty lay in the precise, controlled method of cutting DNA from different sources using "restriction enzymes" to create "cohesive ends" (Claim 8), then joining these pieces together with "enzymatic ligation" (Claim 7), and finally introducing this new hybrid DNA into a living cell to replicate and express the foreign gene. The key was making the foreign DNA functional within a new host and having a way to identify the successful modifications.
What it does not cover
- Does not cover methods for creating recombinant DNA inside a living organism, as it specifies "prepared in vitro" (Claim 1).
- Does not cover inserting DNA into multicellular organisms or complex eukaryotic cells, as it specifies "unicellular organisms" (Claim 1).
- Does not cover methods that do not involve cleaving and ligating DNA segments with "ligatable termini" (Claim 1b).
- Does not cover methods of selection that do not rely on a "phenotypical trait" imparted by the new DNA (Claim 1).
- Does not cover methods where the inserted gene is from the same organism and would naturally exchange genetic information (Claim 11).
Patent Journey
From filing to expiry
Patent Filed
1979
Patent Granted
1980 · 2yr after filing
Highly Cited
346 patents cite this
Patent Expired
1999
PatentBrief Score
Impact Score
Moderate
Citation count
40/40
Highly cited
Claim breadth
10/20
Broad claims
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assignee
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
The original legal language
Original claims
15 claims as filed with the patent office.
Citations
Patent lineage
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