How an Enzyme Helps Find Specific DNA in a Sample
This patent describes a method for detecting a specific DNA sequence in a sample by using a labeled DNA probe and an enzyme that cuts the probe, releasing detectable fragments.
Original patent title: “Homogeneous assay system using the nuclease activity of a nucleic acid polymerase”
This patent describes a method for detecting a specific DNA sequence in a sample by using a labeled DNA probe and an enzyme that cuts the probe, releasing detectable fragments. Granted to Hoffmann La Roche Inc in 1993 with 41 claims and 1,183 forward citations.
Key facts
Coverage
What does this patent actually cover?
This patent describes a process for finding a specific target nucleic acid (like DNA) in a sample. First, the sample is mixed with two short DNA pieces, called oligonucleotides. One oligonucleotide binds to a specific part of the target DNA, and a second, labeled oligonucleotide binds to another nearby part of the same target DNA strand (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1a). Then, an enzyme called a template-dependent nucleic acid polymerase, which has a special ability to cut DNA from its 5' end (5' to 3' nuclease activity), is added (Claim 1b). This enzyme cuts the labeled oligonucleotide, releasing its detectable fragments. Finally, these released labeled fragments are detected and/or measured (Claim 1c). For example, this process can be used to detect a specific viral DNA sequence in a patient sample.
The gap
What does this patent NOT cover?
- Does not cover detection methods that do not use a labeled oligonucleotide.
- Does not cover systems where the nucleic acid polymerase lacks 5' to 3' nuclease activity.
- Does not cover methods where the first oligonucleotide's 3' end is not upstream of the labeled oligonucleotide's 5' end.
- Does not cover detection without the release of labeled fragments.
- Does not cover methods using only a single oligonucleotide probe for detection.
- Does not cover detection methods that rely solely on nucleic acid polymerization without nuclease activity.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The truly novel aspect was using the nucleic acid polymerase's natural 5' to 3' nuclease activity to cleave a labeled probe *during* the DNA synthesis process itself. This allowed for simultaneous amplification and detection, eliminating the need for separate post-amplification detection steps.
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
TaqMan assays for gene expression analysis
Quantitative PCR (qPCR) diagnostics
COVID-19 diagnostic tests
Detection of pathogens in food safety
Genetic screening for inherited diseases
Why it matters
The bigger picture
This patent laid the groundwork for a widely used molecular diagnostic technique known as TaqMan, or probe-based real-time PCR. It provided a way to detect and quantify specific DNA or RNA sequences in real-time during a PCR amplification. This innovation significantly sped up and simplified genetic testing, making it a cornerstone for research, medical diagnostics, and forensic science.
Filed
August 6, 1990
Granted
May 11, 1993
Market context
Who's building on this
Companies in this space
Hoffmann-La Roche, the original assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →, has continued to be a major player in molecular diagnostics. Thermo Fisher Scientific, through its acquisition of Applied Biosystems, is a leading developer and provider of TaqMan-based assays and real-time PCR instruments. Many other diagnostic companies and research institutions globally utilize and build upon this technology for various applications.
Market impact
This patent enabled the development of real-time PCR, which transformed molecular diagnostics and research. It created a new category of in-process detection assays, making DNA/RNA quantification faster and more precise. The technology became an industry standard, leading to widespread adoption in clinical labs, research facilities, and even for environmental monitoring, significantly impacting the speed and accuracy of genetic analysis.
Claim 1 — Plain English
What this patent covers
This patent describes a process for finding a specific target nucleic acid (like DNA) in a sample. First, the sample is mixed with two short DNA pieces, called oligonucleotides. One oligonucleotide binds to a specific part of the target DNA, and a second, labeled oligonucleotide binds to another nearby part of the same target DNA strand (Claim 1a). Then, an enzyme called a template-dependent nucleic acid polymerase, which has a special ability to cut DNA from its 5' end (5' to 3' nuclease activity), is added (Claim 1b). This enzyme cuts the labeled oligonucleotide, releasing its detectable fragments. Finally, these released labeled fragments are detected and/or measured (Claim 1c). For example, this process can be used to detect a specific viral DNA sequence in a patient sample.
The clever bit
The truly novel aspect was using the nucleic acid polymerase's natural 5' to 3' nuclease activity to cleave a labeled probe *during* the DNA synthesis process itself. This allowed for simultaneous amplification and detection, eliminating the need for separate post-amplification detection steps.
What it does not cover
- Does not cover detection methods that do not use a labeled oligonucleotide.
- Does not cover systems where the nucleic acid polymerase lacks 5' to 3' nuclease activity.
- Does not cover methods where the first oligonucleotide's 3' end is not upstream of the labeled oligonucleotide's 5' end.
- Does not cover detection without the release of labeled fragments.
- Does not cover methods using only a single oligonucleotide probe for detection.
- Does not cover detection methods that rely solely on nucleic acid polymerization without nuclease activity.
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
$216K – $691K
Midpoint $432K · 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
41 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Saiki, R. K., Gelfand, D. H., Watson, R. M., & Holland, P. M. (1993). How an Enzyme Helps Find Specific DNA in a Sample (U.S. Patent No. 5,210,015). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/5210015/hcv-pcr-detection
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 an Enzyme Helps Find Specific DNA in a Sample cover?
This patent describes a method for detecting a specific DNA sequence in a sample by using a labeled DNA probe and an enzyme that cuts the probe, releasing detectable fragments.
Who owns patent US 5210015?
Hoffmann La Roche Inc owns this patent, granted in 1993.
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 5210015 cited by?
This patent has been cited by 1183 later patents that build on its ideas.
What problem does this patent solve?
This patent laid the groundwork for a widely used molecular diagnostic technique known as TaqMan, or probe-based real-time PCR. It provided a way to detect and quantify specific DNA or RNA sequences in real-time during a PCR amplification. This innovation significantly sped up and simplified genetic testing, making it a cornerstone for research, medical diagnostics, and forensic science.
What does this patent NOT cover?
Does not cover detection methods that do not use a labeled oligonucleotide.
Same assignee
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