Detecting Genetic Differences Using DNA Probes and Enzymes
This 1987 patent describes a method to find tiny differences in DNA sequences by using special DNA pieces (probes) and cutting enzymes, which can help diagnose genetic conditions like sickle cell anemia.
Original patent title: “Method for detection of polymorphic restriction sites and nucleic acid sequences”
This 1987 patent describes a method to find tiny differences in DNA sequences by using special DNA pieces (probes) and cutting enzymes, which can help diagnose genetic conditions like sickle cell anemia. Granted to Cetus Corp in 1987 with 32 claims and 289 forward citations.
Key facts
Coverage
What does this patent actually cover?
This patent outlines a way to spot specific changes in DNA. You start with a DNA sample and a short, custom-made DNA piece called a probe. This probe is designed to match a specific part of the DNA you're interested in, and it's tagged with a label (like a radioactive marker or a fluorescent dye) near where a potential difference might be. The probe is mixed with the DNA sample, and if the DNA sequence matches, the probe sticks to it. Then, a special enzyme that acts like molecular scissors is used. If the DNA has the specific spot the enzyme cuts, it snips the probe. By separating the cut and uncut probes and looking at their labels, scientists can tell if the specific DNA sequence, and thus the restriction site, is present or absent. ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1 details this process, including hybridizing, digesting with a restriction endonuclease, separating fragments, and detecting. Claim 2 adds a step using a 'blocking oligomer' to make the test more precise by preventing the probe from sticking to similar but incorrect DNA sequences.
The gap
What does this patent NOT cover?
- Methods that do not use an oligonucleotide probe complementary to the target nucleic acid sequence.
- Methods that do not involve digesting the hybridized nucleic acid with a restriction enzyme.
- Methods where the probe is not labeled at the end nearer the restriction site.
- Techniques that do not separate labeled cleaved fragments from labeled uncleaved fragments.
- Methods that do not detect the presence or absence of labeled fragments.
- Detecting nucleic acid sequences without looking for specific restriction sites.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The innovation lies in combining a specifically designed, end-labeled oligonucleotide probe with a restriction enzyme that cuts at a specific site. This allows for a highly sensitive detection system where cutting the probe directly indicates the presence of the target DNA sequence and its associated restriction site, simplifying detection compared to earlier methods.
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
Diagnostic tests for sickle cell anemia
Genetic screening for inherited diseases
Early DNA sequencing and analysis techniques
Research tools for molecular biology
Why it matters
The bigger picture
This patent is foundational for genetic testing and diagnostics. It provided a precise method for identifying genetic variations, which was crucial for understanding and diagnosing inherited diseases. The ability to detect specific DNA sequences and their variations paved the way for personalized medicine and advanced genetic research.
Filed
March 28, 1985
Granted
July 28, 1987
Market context
Who's building on this
Companies in this space
Companies in the diagnostics and biotechnology sectors, including major players like Thermo Fisher Scientific and Roche Diagnostics, continue to build upon the principles of nucleic acid detection and enzymatic analysis. Numerous smaller biotech firms also leverage these fundamental techniques for developing new genetic tests and research reagents.
Market impact
This patent helped establish the field of molecular diagnostics. It enabled the development of specific genetic tests, moving diagnostics from phenotypic observation to direct DNA analysis. This shifted the market towards more precise and earlier disease detection, particularly for inherited conditions, and laid groundwork for the broader genomics revolution.
Claim 1 — Plain English
What this patent covers
This patent outlines a way to spot specific changes in DNA. You start with a DNA sample and a short, custom-made DNA piece called a probe. This probe is designed to match a specific part of the DNA you're interested in, and it's tagged with a label (like a radioactive marker or a fluorescent dye) near where a potential difference might be. The probe is mixed with the DNA sample, and if the DNA sequence matches, the probe sticks to it. Then, a special enzyme that acts like molecular scissors is used. If the DNA has the specific spot the enzyme cuts, it snips the probe. By separating the cut and uncut probes and looking at their labels, scientists can tell if the specific DNA sequence, and thus the restriction site, is present or absent. Claim 1 details this process, including hybridizing, digesting with a restriction endonuclease, separating fragments, and detecting. Claim 2 adds a step using a 'blocking oligomer' to make the test more precise by preventing the probe from sticking to similar but incorrect DNA sequences.
The clever bit
The innovation lies in combining a specifically designed, end-labeled oligonucleotide probe with a restriction enzyme that cuts at a specific site. This allows for a highly sensitive detection system where cutting the probe directly indicates the presence of the target DNA sequence and its associated restriction site, simplifying detection compared to earlier methods.
What it does not cover
- Methods that do not use an oligonucleotide probe complementary to the target nucleic acid sequence.
- Methods that do not involve digesting the hybridized nucleic acid with a restriction enzyme.
- Methods where the probe is not labeled at the end nearer the restriction site.
- Techniques that do not separate labeled cleaved fragments from labeled uncleaved fragments.
- Methods that do not detect the presence or absence of labeled fragments.
- Detecting nucleic acid sequences without looking for specific restriction sites.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
PatentBrief Score
Impact Score
Strong
Citation count
40/40
Highly cited
Claim breadth
20/20
Very broad protection
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
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
$180K – $576K
Midpoint $360K · expired or expiring · industry ×3.0
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
The original legal language
Original claims
32 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Saiki, R. K., & Erlich, H. A. (1987). Detecting Genetic Differences Using DNA Probes and Enzymes (U.S. Patent No. 4,683,194). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/4683194/pcr-process
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 Detecting Genetic Differences Using DNA Probes and Enzymes cover?
This 1987 patent describes a method to find tiny differences in DNA sequences by using special DNA pieces (probes) and cutting enzymes, which can help diagnose genetic conditions like sickle cell anemia.
Who owns patent US 4683194?
Cetus Corp owns this patent, granted in 1987.
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 4683194 cited by?
This patent has been cited by 289 later patents that build on its ideas.
What problem does this patent solve?
This patent is foundational for genetic testing and diagnostics. It provided a precise method for identifying genetic variations, which was crucial for understanding and diagnosing inherited diseases. The ability to detect specific DNA sequences and their variations paved the way for personalized medicine and advanced genetic research.
What does this patent NOT cover?
Methods that do not use an oligonucleotide probe complementary to the target nucleic acid sequence.
Same assignee
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