- Course Introduction
- 01: Evidence & DNA
- 02: Forensic Biology
- 03: DNA Extraction & Quantitation
- 04: DNA Amplification
- Overview
- Introduction
- Amplification
- Primer Design
- Primer Length
- Primer Melting Temperature
- Primer Annealing Temperature
- Values for Tm
- Maximum 3′ Stability
- GC Content Percentage
- No Secondary Structures
- No Self-complementarity
- No Complementarity To Other Primers
- No Long Runs With The Same Base
- Distance Between Two Primers On Target Sequence
- Plateau Effect
- Thermal Cyclers
- Thermal Cycling Parameter and Optimization
- Works Cited & Online Links
- Locus Selection
- Multiplexing
- Contamination
- Overview
- 05: Amplified DNA Product Separation
- 06: STR Data Analysis & Interpretation
- 07: Population Genetics & Statistics
- 08: Communicating Results
- 09: Other DNA Markers & Technologies
- Course Resources
- Laboratory Training Manual
President's DNA Initiative
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Advancing Justice Through DNA Technology
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Advancing Justice Through DNA Technology
DNA Analyst Training
Proprietary Kits
Home > DNA Amplification > Multiplexing > Proprietary Kits
Applied Biosystems and Promega manufacture most forensic STR DNA amplification kits. Each manufacturer has modified their kits to meet the changing needs of the forensic science community. While other manufacturers have developed DNA STR kits, this module focuses on Applied Biosystems and Promega kits because they are currently the most widely used in the forensic science community.
Click here to read about Locus Selection in Subject 04, Module 02.
Each manufacturer has independently developed different primer sets for the Combined DNA Index System (CODIS) core loci. It is possible, albeit rare, to have one set of primers successfully amplify a locus while another fails. The failures are primarily due to primer binding site mutations and the result is a null allele.02
In general, a primer binding site mutation results in a homozygous profile for an actual heterozygote. Both manufacturers have introduced additional primer sets for their kits in an effort to minimize the occurrences of null alleles. When comparing DNA profiles developed from the different manufacturers' kits, it is important to take this into account.
For example, if a kit from manufacturer A types a locus as "12, 14" and a kit from manufacturer B types the same locus as "12" this difference may likely due to a null allele.
